fix: make dependabot commit message follow conventional commits (#55)

* fix: make dependabot commit message follow conventional commits

for conventional commits, see: 
https://www.conventionalcommits.org/en/v1.0.0/

for a good cheat sheet, see:
https://kapeli.com/cheat_sheets/Conventional_Commits.docset/Contents/Resources/Documents/index

* switch to `deps:` commit message prefix

.github/dependabot.yml

@@ -4,3 +4,7 @@ updates:
     directory: "/"
     schedule:
       interval: "weekly"
+    commit-message:
+      # Prefix all commit messages with "deps: ", which should be
+      # accepted as a conventional commit and trigger release-please
+      prefix: "deps"