[IOTDB-1818] Activate dependabot on IoTDB codebase (#4097)

We should use Dependabot to keep IoTDB's dependencies up-to-date.

https://docs.github.com/en/code-security/supply-chain-security/keeping-your-dependencies-updated-automatically/configuration-options-for-dependency-updates

.github/dependabot.yml

@@ -0,0 +1,29 @@
+#
+#  Licensed to the Apache Software Foundation (ASF) under one or more
+#  contributor license agreements.  See the NOTICE file distributed with
+#  this work for additional information regarding copyright ownership.
+#  The ASF licenses this file to You under the Apache License, Version 2.0
+#  (the "License"); you may not use this file except in compliance with
+#  the License.  You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+version: 2
+
+updates:
+  - package-ecosystem: maven
+    directory: "/"
+    schedule:
+      interval: daily
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: daily