Add notes about releasing.

Pull in the script from gtm-session-fetcher to help update the podspec.

Author: thomasvl

DEVELOPMENT.md

@@ -17,7 +17,7 @@ file for how to contribute to this project.
 ## CocoaPods
 
 Install
-  * CocoaPods 1.10.0 (or later)
+  * CocoaPods 1.12.0 (or later)
   * [CocoaPods generate](https://github.com/square/cocoapods-generate) - This is
     not part of the _core_ cocoapods install.
 
@@ -29,3 +29,54 @@ pod gen GoogleAPIClientForREST.podspec --local-sources=./ --auto-open --platform
 
 Note: Set the `--platforms` option to `macos`, `tvos`, or `watchos` to
 develop/test for those platforms.
+
+---
+
+## Releasing
+
+To update the version number and push a release:
+
+1.  Examine what has changed; determine the appropriate new version number.
+
+1.  Update the version number.
+
+    Run the `update_version.py` script to update the appropriate files with the
+    new version number, by passing in the new version (must be in X.Y.Z format).
+
+    ```sh
+    $ ./update_version.py 3.2.1
+    ```
+
+    Submit the changes to the repo.
+
+1.  Create a release on Github.
+
+    Top left of the [project's release page](https://github.com/google/google-api-objectivec-client-for-rest/releases)
+    is _Draft a new release_.
+
+    The tag should be vX.Y.Z where the version number X.Y.Z _exactly_ matches
+    the one you provided to the `update_version.py` script. (GoogleAPIClientForREST
+    has a `v` prefix on its tags.)
+
+    For the description call out any major changes in the release. Usually the
+    _Generate release notes_ button in the toolbar is a good starting point and
+    just updating as need for more/less detail (dropping comments about CI,
+    updating the version number, etc.).
+
+1.  Publish the CocoaPod.
+
+    NOTE: You must be a registered owner of the podspec and be "logged in" from
+    the CocoaPods pov locally to do this. The general google account for pods is
+    and owner and can be used for releases.
+
+    ```sh
+    $ pod trunk push --skip-import-validation --skip-tests GoogleAPIClientForREST.podspec
+    ```
+
+    NOTE: Since validations are run on CI during every PR/commit, they are skipped here
+    because publish takes a long time. And M2 based MBP can take > 1 hour to do this
+    because of all of the subspecs and because the pod supports all of Apple platforms.
+    
+    The tests are skipped because Cocoapods has had issues with running watchOS tests
+    based on the local machines config. Those are also covered in github CI, so this
+    should be good.

update_version.py

@@ -0,0 +1,48 @@
+#! /usr/bin/python3
+# update_version.py.py - Helper for the library's version number
+#
+# Copyright 2017 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import re
+import sys
+
+_PROJECT_ROOT = os.path.dirname(os.path.abspath(__file__))
+_PODSPEC_PATH = os.path.join(_PROJECT_ROOT, 'GoogleAPIClientForREST.podspec')
+
+
+def main(args):
+  if len(args) != 1:
+    sys.stderr.write('update_version.py VERSION\n')
+    sys.exit(1)
+
+  ver_str = args[0]
+  if len(ver_str.split('.')) != 3:
+    sys.stderr.write('Version should always be three segments.\n')
+    sys.exit(1)
+
+  # podspec
+  pod_content = open(_PODSPEC_PATH).read()
+  pod_content = re.sub(r'version      = \'\d+\.\d+\.\d+\'',
+                       'version      = \'%s\'' % (ver_str,),
+                       pod_content)
+  assert ver_str in pod_content
+  open(_PODSPEC_PATH, 'w').write(pod_content)
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))