Adding 4.2.x to dependabot

Signed-off-by: Ryan Baxter <ryan.baxter@broadcom.com>

.github/dependabot.yml

@@ -5,6 +5,11 @@ updates:
     target-branch: "4.1.x"
     schedule:
       interval: "weekly"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    target-branch: "4.2.x"
+    schedule:
+      interval: "weekly"
   - package-ecosystem: "github-actions"
     directory: "/"
     target-branch: "main"
@@ -21,6 +26,17 @@ updates:
         update-types:
           - version-update:semver-major
           - version-update:semver-minor
+  - package-ecosystem: maven
+    directory: /
+    schedule:
+      interval: daily
+    target-branch: 4.2.x
+    ignore:
+      # only upgrade patch versions for maintenance branch
+      - dependency-name: "*"
+        update-types:
+          - version-update:semver-major
+          - version-update:semver-minor
   - package-ecosystem: maven
     directory: /
     schedule:
@@ -46,3 +62,8 @@ updates:
     directory: /docs
     schedule:
       interval: weekly
+  - package-ecosystem: npm
+    target-branch: 4.2.x
+    directory: /docs
+    schedule:
+      interval: weekly