cordova-fetch patch release August 2018

Patch release wanted with the following updates:

• repo URL fix from https://github.com/apache/cordova-fetch/pull/20
• explicit requirement for cordova-common@2.2.5 (or cordova-common@^2.2.5) in dependencies, which would be an in-range update (not wanted in master branch, see note below)

Following steps at https://github.com/apache/cordova-coho/blob/master/docs/tools-release-process.md (with some minor adjustments)

Note: cordova-common@^2.2.5 dependency update is not wanted in master branch. The master branch of this and other Cordova repos should now target the next major release as discussed in this dev@cordova.apache.org thread.