chore(deps): add LTS Dependabot configuration

This is an experimental change which (hopefully) enables Dependabot on
the LTS branches, and ensures that PRs touching the package management
files in the repository assign the proper developer(s) as reviewers.

Change-Id: Iefa2f46325514026969fabd08e550544dcb4a598
Signed-off-by: Chris Kay <chris.kay@arm.com>

.github/CODEOWNERS

@@ -0,0 +1,5 @@
+package.json @CJKay
+package-lock.json @CJKay
+
+pyproject.toml @CJKay
+poetry.lock @CJKay

.github/dependabot.yml

@@ -0,0 +1,37 @@
+version: 2
+updates:
+  - target-branch: "main"
+    package-ecosystem: "npm"
+    directories: ["/"]
+    schedule:
+      interval: "daily"
+
+  - target-branch: "lts-v2.10"
+    package-ecosystem: "npm"
+    directories: ["/"]
+    schedule:
+      interval: "daily"
+
+  - target-branch: "lts-v2.8"
+    package-ecosystem: "npm"
+    directories: ["/"]
+    schedule:
+      interval: "daily"
+
+  - target-branch: "main"
+    package-ecosystem: "pip"
+    directories: ["/", "/tools/cot_dt2c", "/tools/tlc"]
+    schedule:
+      interval: "daily"
+
+  - target-branch: "lts-v2.10"
+    package-ecosystem: "pip"
+    directories: ["/"]
+    schedule:
+      interval: "daily"
+
+  - target-branch: "lts-v2.8"
+    package-ecosystem: "pip"
+    directories: ["/"]
+    schedule:
+      interval: "daily"