Migrate from CircleCI to Github Actions (#98)

CI/CD reusable workflows in Github Actions for Plugin software lifecycle

Ticket: https://mattermost.atlassian.net/browse/CLD-4816

Author: spirosoik

.circleci/config.yml

@@ -0,0 +1,18 @@
+name: cd
+on:
+  workflow_run:
+    workflows: ["ci"]
+    branches-ignore: ["*"]
+    types:
+      - completed
+  push:
+    tags:
+      - "^v.*"
+
+permissions:
+  contents: read
+
+jobs:
+  plugin-cd:
+    uses: mattermost/actions-workflows/.github/workflows/plugin-cd.yml@main
+    secrets: inherit

.github/workflows/cd.yml

@@ -0,0 +1,18 @@
+name: ci
+on:
+  schedule:
+    - cron: "0 0 * * *"
+  push:
+    branches:
+      - master
+    tags:
+      - "^v.*"
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  plugin-ci:
+    uses: mattermost/actions-workflows/.github/workflows/plugin-ci.yml@main
+    secrets: inherit

.github/workflows/ci.yml

@@ -0,0 +1 @@
+14.21.1