CocoaPods找不到与"Firebase/Core" | cloud_firestore，Flutter兼容的版本。

我在pod中遇到了一些问题，请见下文

在debug模式下将lib/main.dart启动到iPhone X...

正在运行pod install...

CocoaPods输出：

↳

准备中

Analyzing dependencies
Inspecting targets to integrate
  Using `ARCHS` setting to build architectures of target `Pods-Runner`: (``)
Fetching external sources
-> Fetching podspec for `Flutter` from `.symlinks/flutter/ios`
-> Fetching podspec for `cloud_firestore` from `.symlinks/plugins/cloud_firestore/ios`
-> Fetching podspec for `firebase_core` from `.symlinks/plugins/firebase_core/ios`
-> Fetching podspec for `shared_preferences` from `.symlinks/plugins/shared_preferences/ios`
-> Fetching podspec for `url_launcher` from `.symlinks/plugins/url_launcher/ios`
Resolving dependencies of `Podfile`
[!] CocoaPods could not find compatible versions for pod "Firebase/Core":
  In Podfile:
    cloud_firestore (from `.symlinks/plugins/cloud_firestore/ios`) was resolved to 0.0.1, which depends on
      Firebase/Core
Specs satisfying the `Firebase/Core` dependency were found, but they required a higher minimum deployment target.
CocoaPods could not find compatible versions for pod "GoogleUtilities/MethodSwizzler":
  In Podfile:
    cloud_firestore (from `.symlinks/plugins/cloud_firestore/ios`) was resolved to 0.0.1, which depends on
      Firebase/Core was resolved to 5.8.0, which depends on
        FirebaseAnalytics (= 5.1.2) was resolved to 5.1.2, which depends on
          GoogleUtilities/MethodSwizzler (~> 5.2.0)
Specs satisfying the `GoogleUtilities/MethodSwizzler (~> 5.2.0)` dependency were found, but they required a higher minimum deployment target.
CocoaPods could not find compatible versions for pod "gRPC-Core":
  In Podfile:
    cloud_firestore (from `.symlinks/plugins/cloud_firestore/ios`) was resolved to 0.0.1, which depends on
      Firebase/Firestore was resolved to 5.8.0, which depends on
        FirebaseFirestore (= 0.13.3) was resolved to 0.13.3, which depends on
          gRPC-C++ (~> 0.0.3) was resolved to 0.0.3, which depends on
            gRPC-C++/Implementation (= 0.0.3) was resolved to 0.0.3, which depends on
              gRPC-Core (= 1.14.0)
    cloud_firestore (from `.symlinks/plugins/cloud_firestore/ios`) was resolved to 0.0.1, which depends on
      Firebase/Firestore was resolved to 5.8.0, which depends on
        FirebaseFirestore (= 0.13.3) was resolved to 0.13.3, which depends on
          gRPC-ProtoRPC (~> 1.0) was resolved to 1.14.1, which depends on
            gRPC-ProtoRPC/Main (= 1.14.1) was resolved to 1.14.1, which depends on
              gRPC (= 1.14.1) was resolved to 1.14.1, which depends on
                gRPC/Main (= 1.14.1) was resolved to 1.14.1, which depends on
                  gRPC-Core (= 1.14.1)
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolution.rb:328:in `raise_error_unless_state'
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolution.rb:310:in `block in unwind_for_conflict'
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolution.rb:308:in `tap'
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolution.rb:308:in `unwind_for_conflict'
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolution.rb:684:in `attempt_to_activate'
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolution.rb:254:in `process_topmost_state'
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolution.rb:182:in `resolve'
/Library/Ruby/Gems/2.3.0/gems/molinillo-0.6.5/lib/molinillo/resolver.rb:43:in `resolve'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/resolver.rb:123:in `resolve'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/installer/analyzer.rb:781:in `block in resolve_dependencies'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/user_interface.rb:64:in `section'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/installer/analyzer.rb:779:in `resolve_dependencies'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/installer/analyzer.rb:88:in `analyze'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:243:in `analyze'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:154:in `block in resolve_dependencies'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/user_interface.rb:64:in `section'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:153:in `resolve_dependencies'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:116:in `install!'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/command/install.rb:41:in `run'
/Library/Ruby/Gems/2.3.0/gems/claide-1.0.2/lib/claide/command.rb:334:in `run'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/command.rb:52:in `run'
/Library/Ruby/Gems/2.3.0/gems/cocoapods-1.5.3/bin/pod:55:in `'
/usr/local/bin/pod:22:in `load'
/usr/local/bin/pod:22:in `

CocoaPods的错误输出：

↳

[33m警告：CocoaPods需要您的终端使用UTF-8编码。

考虑将以下内容添加到~/.profile文件中：

    export LANG=en_US.UTF-8
    [0m
[!] Automatically assigning platform `ios` with version `8.0` on target `Runner` because no platform was specified. Please specify a platform for this target in your Podfile. See `https://guides.cocoapods.org/syntax/podfile.html#platform`.

运行pod install时出错

在iPhone X上启动应用程序时出错。