dependabot: Ignore serde minor versions (#76)

Author: sjoerdsimons

.github/dependabot.yaml

@@ -23,6 +23,10 @@ updates:
         update-types:
           - "version-update:semver-minor"
           - "version-update:semver-patch"
+      - dependency-name: "serde"
+        update-types:
+          - "version-update:semver-minor"
+          - "version-update:semver-patch"
       - dependency-name: "*"
         update-types:
           - "version-update:semver-patch"