Exclude dependabot PRs from changelog (#576)

Dependabot commits add a lot of noise to the release notes - we only
want user-facing changes in there. This config skips dependabot PRs when
creating the changelog.

Signed-off-by: Ajeet D'Souza <98ajeet@gmail.com>

Author: ajeetdsouza

.github/release.yaml

@@ -0,0 +1,6 @@
+changelog:
+  exclude:
+    labels:
+      - ignore-for-release
+    authors:
+      - dependabot[bot]