add aarch64 build (#599)

Hi,

In asahi linux (aarch64), selene is not available in neovim because
mason can not download an artifact for it (there is no aarch64 linux on
github releases). To fix this, I added a cross compilation step to
generate and upload an aarch64 linux binary.

I tested this in my fork, and it correctly generates aarch64 binaries.

Please let me know if you like something changed!

Co-authored-by: boyned//Kampfkarren <boynedmaster@gmail.com>

.github/workflows/build.yml

@@ -78,6 +78,18 @@ jobs:
       with:
         name: selene-linux
         path: ./target/release/selene
+    - name: Build arm64 (Default features)
+      uses: actions-rs/cargo@v1
+      with:
+        working-directory: selene
+        use-cross: true
+        command: build
+        args: --locked --release --target aarch64-unknown-linux-gnu
+    - name: Upload selene arm64
+      uses: actions/upload-artifact@v1
+      with:
+        name: selene-linux-aarch64
+        path: ./target/aarch64-unknown-linux-gnu/release/selene
   build_linux_light:
     runs-on: ubuntu-latest
     steps:
@@ -91,6 +103,18 @@ jobs:
       with:
         name: selene-light-linux
         path: ./target/release/selene
+    - name: Build arm64 (Lightweight)
+      uses: actions-rs/cargo@v1
+      with:
+        working-directory: selene
+        use-cross: true
+        command: build
+        args: --locked --release --verbose --no-default-features --target aarch64-unknown-linux-gnu
+    - name: Upload selene-light arm64
+      uses: actions/upload-artifact@v1
+      with:
+        name: selene-light-linux-aarch64
+        path: ./target/aarch64-unknown-linux-gnu/release/selene
   release:
     runs-on: ubuntu-latest
     needs: ['build_windows_light', 'build_windows', 'build_mac', 'build_mac_light', 'build_linux', 'build_linux_light']