Updated Podfile to absorb changes to WordPressKit

[ghost]

Supports the resolution of [this issue](wordpress-mobile/WordPressKit-iOS#86
wordpress-mobile/WordPressKit-iOS#79) in WordPressKit.

I've designated this a Draft PR, unless or until the associated update to WordPressKit has been properly versioned.

To test:

• Branch should build.
• Tests should pass.
• "Smoke test" of network connectivity in the app should work.

Update release notes:

• If there are user facing changes, I have added an item to RELEASE-NOTES.txt.

[ghost]

@jklausa would you be willing to take a look at this?

[ghost]

@jklausa please hold on this. I absorbed the change to WordPressKit that you just approved, and am now faced with a merge conflict.

In attempting to resolve said conflict, I encountered the following error:

[!] CocoaPods could not find compatible versions for pod "WordPressShared":
  In snapshot (Podfile.lock):
    WordPressShared (= 1.7.1, = 1.7.1-beta.3, ~> 1.4)

  In Podfile:
    WordPressKit (~> 2.1.1-beta.1) was resolved to 2.1.1-beta.1, which depends on
      WordPressShared (~> 1.4)

    WordPressShared (~> 1.7.1)

Due to the previous naïve CocoaPods resolver, you were using a pre-release version of `WordPressShared`, without explicitly asking for a pre-release version, which now leads to a conflict. Please decide to either use that pre-release version by adding the version requirement to your Podfile (e.g. `pod 'WordPressShared', '= 1.7.1, = 1.7.1-beta.3, ~> 1.4'`) or revert to a stable version by running `pod update WordPressShared`.

I'm afraid I might have to re-revise WordPressKit to account for the change to WordPressShared.

[ghost]

OK @jklausa - thanks to an assist from @jkmassel, no version increment was required here. Ready when you are!

[jklausa]

@stevebaranski I ended up needing to roll those changes among others as part of #11129 — would you mind if we closed this and just merged #11129 instead?

[ghost]

Sounds good @jklausa - thank you!

[ghost]

Closing this issue in deference to #11129.