Update CI configuration (#8)

* Leverage centralized workflow configuration
* Update scheduled run so it executes _after_ nightlies are published

.github/workflows/athena.yml

@@ -0,0 +1,12 @@
+name: Athena
+
+on:
+  pull_request:
+    branches:
+      - 'master'
+  schedule:
+    - cron: '37 0 * * *' # Nightly at 00:37
+
+jobs:
+  CI:
+    uses: athena-framework/actions/.github/workflows/ci.yml@master

.github/workflows/ci.yml

@@ -1,48 +0,0 @@
-name: CI
-
-on:
-  pull_request:
-    branches:
-      - 'master'
-  schedule:
-    - cron: '0 21 * * *'
-
-jobs:
-  check_format:
-    runs-on: ubuntu-latest
-    container:
-      image: crystallang/crystal:latest-alpine
-    steps:
-      - uses: actions/checkout@v2
-      - name: Format
-        run: crystal tool format --check
-  coding_standards:
-    runs-on: ubuntu-latest
-    container:
-      image: crystallang/crystal:latest-alpine
-    steps:
-      - uses: actions/checkout@v2
-      - name: Install Dependencies
-        run: shards install
-      - name: Ameba
-        run: ./bin/ameba
-  test_latest:
-    runs-on: ubuntu-latest
-    container:
-      image: crystallang/crystal:latest-alpine
-    steps:
-      - uses: actions/checkout@v2
-      - name: Install Dependencies
-        run: shards install
-      - name: Specs
-        run: crystal spec --order random --error-on-warnings
-  test_nightly:
-    runs-on: ubuntu-latest
-    container:
-      image: crystallang/crystal:nightly-alpine
-    steps:
-      - uses: actions/checkout@v2
-      - name: Install Dependencies
-        run: shards install
-      - name: Specs
-        run: crystal spec --order random --error-on-warnings