fix: syncplay server errors

Dockerfile

@@ -10,6 +10,8 @@ RUN cat /dev/null > requirements_gui.txt
 RUN SNAPCRAFT_PART_BUILD=1 pip wheel --wheel-dir /wheels/ ./
 
 FROM ${PYTHON} AS syncplay
+WORKDIR /wheels/
+RUN pip wheel PyYaml
 COPY --from=builder /wheels/ /wheels/
 WORKDIR /release/local/lib/
 RUN mkdir $(basename /usr/local/lib/python3.*/) && cd ./python3.*/ && \

boot.py

@@ -23,7 +23,7 @@ def temp_file(file: str, content: str) -> str:
     """ Create and save content to temporary files. """
     file = os.path.join('/tmp/', file)
     with open(file, 'w') as fp:
-        fp.write(f'{content}\n')
+        fp.write(content)
     return file
 
 
@@ -67,7 +67,7 @@ def load_config(args: dict[str, Any], file: str) -> dict[str, Any]:
 
 def build_args(opts: dict):
     """ Construct the startup arguments for syncplay server. """
-    args = ['--port', opts.get('port', '8999')]
+    args = ['--port', str(opts.get('port', 8999))]
     if 'password' in opts:
         args += ['--password', opts['password']]
     if 'motd' in opts: