ci(commitlint): Only warn on subject-case mismatch

The Angular reference for the summary [1] demands "don't capitalize the
first letter" and Renovate adheres to it (without making it
configurable yet [2]), so only warn here in order to accept Renovate PRs.

[1]: https://github.com/angular/angular/blob/main/CONTRIBUTING.md#summary
[2]: renovatebot/renovate#12062

Signed-off-by: Sebastian Schuberth <[email protected]>

Author: sschuberth

.commitlintrc.yml

@@ -26,7 +26,7 @@ rules:
       - snake-case
       - upper-case
   subject-case:
-    - 2
+    - 1
     - always
     - - pascal-case
       - sentence-case