Add GitHub Actions to run tests for default and #![no_std] modes

.github/workflows/test.yml

@@ -0,0 +1,36 @@
+name: Rust
+
+on:
+  pull_request:
+  push:
+
+jobs:
+  check:
+    name: Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ATiltedTree/setup-rust@v1
+        with:
+          rust-version: stable
+      - run: cargo check
+
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ATiltedTree/setup-rust@v1
+        with:
+          rust-version: stable
+      - run: cargo test
+  
+  test_no_default_features:
+    name: Test (no default features)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ATiltedTree/setup-rust@v1
+        with:
+          rust-version: stable
+      - run: cargo test --no-default-features