👷 ci(bot): init some configs [no ci]

Author: webup

.github/auto_assign.yml

@@ -0,0 +1,22 @@
+# Set to true to add reviewers to pull requests
+addReviewers: true
+
+# Set to author to set pr creator as assignee
+addAssignees: author
+
+# A list of reviewers to be added to pull requests (GitHub user name)
+reviewers:
+  - webup
+  - benjaminhuo
+
+# A number of reviewers added to the pull request
+# Set 0 to add all the reviewers (default: 0)
+numberOfReviewers: 1
+
+# A list of keywords to be skipped the process that add reviewers if pull requests include it
+skipKeywords:
+  - wip
+
+# A list of users to be skipped by both the add reviewers and add assignees processes
+skipUsers:
+  - dependabot[bot]

.github/labeler.yml

@@ -0,0 +1,25 @@
+# Number of labels to fetch (optional). Defaults to 100
+numLabels: '40'
+# These labels will not be used even if the issue contains them (optional).
+# Pass a blank array if no labels are to be excluded.
+# excludeLabels: []
+excludeLabels:
+  - pinned
+# custom configuration to override default behaviour
+# control explicitly what gets added and when
+# custom:
+#   - location: title
+#     keywords:
+#       - enable
+#     labels:
+#       - enhancement
+#   - location: title
+#     keywords:
+#       - fix
+#     labels:
+#       - bug
+#   - location: title
+#     keywords:
+#       - doc
+#     labels:
+#       - documentation

.github/mergable.yml

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+version: 2
+mergeable:
+  - when: pull_request.*
+    name: 'Ingore WIP'
+    validate:
+      - do: title
+        must_exclude:
+          regex: ^\[WIP\]
+      - do: label
+        must_exclude:
+          regex: 'wip'
+  - when: pull_request.*
+    name: 'NO empty description'
+    validate:
+      - do: description
+        no_empty:
+          enabled: true
+          message: Description matter and should not be empty. Provide detail with either **what** was changed, **why** it was changed, or **how** it was changed.
+  - when: schedule.repository
+    name: 'Check stale PR and issues'
+    validate:
+      - do: stale
+        days: 20
+        type: pull_request, issues
+    pass:
+      - do: comment
+        payload:
+          body: This is old. Is it still relevant?
+  - when: pull_request.opened
+    name: 'Greet a contributor'
+    validate: []
+    pass:
+      - do: comment
+        payload:
+          body: >
+            Thanks for creating a pull request! A maintainer will review your changes shortly. Please don't be discouraged if it takes a while.
+  - when: pull_request.*, pull_request_review.*
+    name: 'Draft check'
+    validate:
+      - do: payload
+        pull_request:
+          draft:
+            boolean:
+              match: false
+    fail:
+      - do: comment
+        payload:
+          body: This PR is STILL a draft!