chore: add gitlint config file

This commit adds the same .gitlint configuration file we have in
release-service and release-service-utils.

Signed-off-by: Johnny Bieren <jbieren@redhat.com>

.gitlint

@@ -0,0 +1,18 @@
+[general]
+contrib=contrib-title-conventional-commits,CC1
+extra-path=.github/gitlint
+ignore=T5
+
+[title-max-length]
+line-length=72
+
+[body-max-line-length]
+line-length=88
+
+[body-first-line-empty]
+
+[contrib-title-conventional-commits]
+
+[ignore-by-author-name]
+regex=(.*)\[bot\](.*)
+ignore=T1,B1