ci: move to github actions / remove circleci config

.circleci/config.yml

-version: 2
-
-defaults: &defaults
-  docker:
-    - image: vuejs/ci
-
-step_restore_cache: &restore_cache
-  restore_cache:
-    keys:
-      - v1-dependencies-{{ checksum "yarn.lock" }}-1
-      - v1-dependencies-
-
-step_install_deps: &install_deps
-  run:
-    name: Install Dependencies
-    command: yarn --frozen-lockfile
-
-step_save_cache: &save_cache
-  save_cache:
-    paths:
-      - node_modules
-      - packages/compiler-core/node_modules
-      - packages/compiler-sfc/node_modules
-      - packages/vue/node_modules
-      - ~/.cache/yarn
-    key: v1-dependencies-{{ checksum "yarn.lock" }}-1
-
-jobs:
-  test:
-    <<: *defaults
-    steps:
-      - checkout
-      - *restore_cache
-      - *install_deps
-      - *save_cache
-      - run: yarn test --ci
-
-  test-dts:
-    <<: *defaults
-    steps:
-      - checkout
-      - *restore_cache
-      - *install_deps
-      - *save_cache
-      - run: yarn test-dts
-
-workflows:
-  version: 2
-  ci:
-    jobs:
-      - test
-      - test-dts

.github/workflows/ci.yml

-name: 'test'
+name: 'ci'
 on:
   push:
     branches: