Add targets to docker image, test pipeline temporarily on PR

.gitea/workflows/harmony_composer.yaml

@@ -1,5 +1,6 @@
 name: Compile and package harmony_composer
 on:
+  pull_request:
   push:
     branches:
       - main

Dockerfile

@@ -10,6 +10,16 @@ FROM docker.io/rust:1.87.0
 
 WORKDIR /app
 
+RUN apt update
+
+RUN rustup target add x86_64-unknown-linux-gnu
+
+RUN apt install -y mingw-w64
+RUN rustup target add x86_64-pc-windows-gnu
+
+RUN apt install -y gcc-aarch64-linux-gnu
+RUN rustup target add aarch64-unknown-linux-gnu
+
 COPY --from=build /app/target/release/harmony_composer .
 
 ENTRYPOINT ["/app/harmony_composer"]