Update Dependabot to allow major version updates (#22)

Author: gionn

.github/dependabot.yaml

@@ -18,11 +18,6 @@ updates:
         update-types:
           - "patch"
     ignore:
-      # Major version updates
-      - dependency-name: "*"
-        update-types:
-          - "version-update:semver-major"
-
       # Ignore self updates to prevent infinite updates
       # TODO deal the self update mechanism with a custom workflow
       - dependency-name: "nuxeo/gh-build-tools"