v0.3.1: automated releases + version-drift check

The "Automated releases" entry was written under v0.3.0, but that commit landed
after the v0.3.0 tag -- the CHANGELOG was claiming the release contained something
it did not. Moved to its own version rather than left as a quiet inaccuracy.

Bumps VERSION to 0.3.1 across all four scripts, which the new consistency check
now enforces.

uninstall.sh

@@ -3,7 +3,7 @@
 
 set -euo pipefail
 
-VERSION="0.3.0"
+VERSION="0.3.1"
 
 PATCH_DIR="$(cd "$(dirname "$0")" && pwd)"
 _HOOK_COMMENT='TrueCloud provider patch (S3/B2)'