Fix CI (#1)

Author: DilumAluthge

.github/workflows/CI.yml renamed to .github/workflows/ci.yml

@@ -1,7 +1,12 @@
 name: CI
 on:
-  - push
-  - pull_request
+  pull_request:
+    branches:
+      - master
+  push:
+    branches:
+      - master
+    tags: '*'
 jobs:
   test:
     name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}
@@ -10,14 +15,21 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.6'
-          - '1.7'
+          - '^1.6.0-0' # delete this line once Julia 1.6 is released
+          # - '1.6'    # uncomment this line once Julia 1.6 is released
+          # - '1'      # uncomment this line once Julia 1.6 is released
           - 'nightly'
         os:
           - ubuntu-latest
+          - macos-latest
+          - windows-latest
         arch:
           - x64
           - x86
+        # 32-bit Julia binaries are not available on macOS
+        exclude:
+          - os: macOS-latest
+            arch: x86
     steps:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@v1
@@ -47,7 +59,8 @@ jobs:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@v1
         with:
-          version: '1'
+          version: '^1.6.0-0' # delete this line once Julia 1.6 is released
+          version: '1'        # uncomment this line once Julia 1.6 is released
       - run: |
           julia --project=docs -e '
             using Pkg