chore: make max-header-length in commitlint a warning

dependabot sometimes creates commit messages that violate this rule. nothing we can do about it at the moment. see #8

.commitlintrc.json

@@ -1 +1,6 @@
-{ "extends": ["@commitlint/config-conventional"] }
+{
+  "extends": ["@commitlint/config-conventional"],
+  "rules": {
+    "header-max-length": [1, "always", 72]
+  }
+}