[!] Unable to determine Swift version for the following pods:

原因工程中沒有設定SWIFT_VERSION，為空，而依賴的第三方庫使用了swift，若用公司網絡下載下傳pods下載下傳不下來，建議采用電腦直接連接配接手機wifi網絡（你的手機流量夠用的情況下）。

解決方案：設定Targets->Build Settings->Combined(All)->User-Defined->SWIFT_VERSION，設定為4.0等。若沒有SWIFT_VERSION屬性就要在User-Defined下面點“+”添加，設定版本号。

-> Installing Zip (1.1.0)
 > Git download
 > Git download
     $ /usr/bin/git clone https://github.com/marmelroy/Zip.git
     /var/folders/4y/m9ckznh17111xdfwvn7xg0w40000gn/T/d20190611-5196-5q9vsg
     --template= --single-branch --depth 1 --branch 1.1.0
     Cloning into '/var/folders/4y/m9ckznh17111xdfwvn7xg0w40000gn/T/d20190611-5196-5q9vsg'...
     Note: checking out 'e0935dcb2c99f4511ecf95cab5dcec0f25335829'.

     You are in 'detached HEAD' state. You can look around, make experimental
     changes and commit them, and you can discard any commits you make in this
     state without impacting any branches by performing another checkout.

     If you want to create a new branch to retain commits you create, you may
     do so (now or later) by using -b with the checkout command again. Example:

       git checkout -b <new-branch-name>

  > Copying Zip from
  `/Users/jiaguoshang/Library/Caches/CocoaPods/Pods/Release/Zip/1.1.0-8877e` to
  `Pods/Zip`

-> Installing iOSDFULibrary (4.2.2)
 > Git download
 > Git download
     $ /usr/bin/git clone
     https://github.com/NordicSemiconductor/IOS-Pods-DFU-Library.git
     /var/folders/4y/m9ckznh17111xdfwvn7xg0w40000gn/T/d20190611-5196-1xw1fjc
     --template= --single-branch --depth 1 --branch 4.2.2
     Cloning into '/var/folders/4y/m9ckznh17111xdfwvn7xg0w40000gn/T/d20190611-5196-1xw1fjc'...
     Note: checking out '422caf59d89f1ded7e9f403f17a5ea863b6b40ff'.

     You are in 'detached HEAD' state. You can look around, make experimental
     changes and commit them, and you can discard any commits you make in this
     state without impacting any branches by performing another checkout.

     If you want to create a new branch to retain commits you create, you may
     do so (now or later) by using -b with the checkout command again. Example:

       git checkout -b <new-branch-name>

  > Copying iOSDFULibrary from
  `/Users/jiaguoshang/Library/Caches/CocoaPods/Pods/Release/iOSDFULibrary/4.2.2-65a30`
  to `Pods/iOSDFULibrary`
  - Running pre install hooks
[!] Unable to determine Swift version for the following pods:

- `Zip` does not specify a Swift version and none of the targets (`ELock_Example`) integrating it have the `SWIFT_VERSION` attribute set. Please contact the author or set the `SWIFT_VERSION` attribute in at least one of the targets that integrate this pod.