fix Dockerfile, also build and test develop branch

Author: chocolatkey

.github/workflows/build.yml

@@ -2,7 +2,7 @@ name: Build and Test
 
 on:
   push:
-    branches: [ main ]
+    branches: [ main, develop ]
   pull_request:
     branches: [ '**' ]
 

Dockerfile

@@ -40,7 +40,6 @@ ADD https://readium-playground-files.storage.googleapis.com/demo/moby-dick.epub
 ADD https://readium-playground-files.storage.googleapis.com/demo/BellaOriginal3.epub /srv/publications/
 
 # Copy built Go binary
-COPY X                   dist/rwp_linux_amd64_v3/rwp
 COPY --from=builder /app/dist/rwp_linux_amd64_v3/rwp /opt/
 
 EXPOSE 15080