Enable GitHub Actions and fix file URL behavior (#1232)

* Use GitHub Actions

* Fix unused imports on Windows

* Fix test for Windows

* Stop to run CI for i686-pc-windows-msvc for now

* Use `/` instead of `\` on Windows

* Add entry to changelog

* Prepare actix-files release

.github/workflows/main.yml

@@ -0,0 +1,67 @@
+name: CI
+
+on: [push, pull_request]
+
+env:
+  VCPKGRS_DYNAMIC: 1
+
+jobs:
+  build_and_test:
+    strategy:
+      fail-fast: false
+      matrix:
+        toolchain:
+          - x86_64-pc-windows-msvc
+          # - i686-pc-windows-msvc
+          - x86_64-apple-darwin
+        version:
+          - stable
+          - nightly
+        include:
+        - toolchain: x86_64-pc-windows-msvc
+          os: windows-latest
+          arch: x64
+        # - toolchain: i686-pc-windows-msvc
+          # os: windows-latest
+          # arch: x86
+        - toolchain: x86_64-apple-darwin
+          os: macOS-latest
+
+    name: ${{ matrix.version }} - ${{ matrix.toolchain }}
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@master
+
+      - name: Install ${{ matrix.version }}
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.version }}-${{ matrix.toolchain }}
+          default: true
+
+      - name: Install OpenSSL
+        if: matrix.os == 'windows-latest'
+        run: |
+          vcpkg integrate install
+          vcpkg install openssl:${{ matrix.arch }}-windows
+
+      - name: check nightly
+        if: matrix.version == 'nightly'
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+          args: --all --benches --bins --examples --tests
+
+      - name: check stable
+        if: matrix.version == 'stable'
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+          args: --all --bins --examples --tests
+
+      - name: tests
+        if: matrix.toolchain != 'x86_64-pc-windows-gnu'
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --all --all-features -- --nocapture