Use dedicated bumpversion config file

.bumpversion.cfg

@@ -0,0 +1,16 @@
+[bumpversion]
+current_version = 1.2.3
+commit = True
+tag = True
+
+[bumpversion:file:thunderbird/__version__.py]
+search = __version__ = "{current_version}"
+replace = __version__ = "{new_version}"
+
+[bumpversion:file:Dockerfile]
+search = Version="{current_version}"
+replace = Version="{new_version}"
+
+[bumpversion:file:.cruft.json]
+search = "version": "{current_version}"
+replace = "version": "{new_version}"

docs/dev_guide.md

@@ -55,9 +55,9 @@ Make a new version of `thunderbird` in the following steps:
 
 * Make sure everything is committed to GitHub.
 * Update `CHANGES.md` with the next version.
-* Dry Run: `bumpversion --dry-run --verbose --new-version 0.8.1 patch`
-* Do it: `bumpversion --new-version 0.8.1 patch`
-* ... or: `bumpversion --new-version 0.9.0 minor`
+* Dry Run: `bumpversion --dry-run --verbose patch`
+* Do it: `bumpversion patch`
+* ... or: `bumpversion minor`
 * Push it: `git push`
 * Push tag: `git push --tags`