Fix plugin installdir

This ensures that the plugin is picked up at runtime without any
additional configuration.

Author: dominiklohmann

Dockerfile

@@ -5,7 +5,7 @@ COPY . /tmp/trim/
 
 RUN cmake -S /tmp/trim -B /tmp/trim/build -G Ninja -D CMAKE_INSTALL_PREFIX:STRING="$PREFIX"
 RUN cmake --build /tmp/trim/build --parallel
-RUN cmake --install /tmp/trim/build --strip --component Runtime --prefix /opt/tenzir/plugin/trim
+RUN cmake --install /tmp/trim/build --strip --component Runtime --prefix /tmp/trim/install
 
 FROM builder AS test
 
@@ -15,4 +15,4 @@ ENTRYPOINT cmake --build /tmp/trim/build --target update-integration
 
 FROM ghcr.io/tenzir/tenzir:${TENZIR_VERSION}
 
-COPY --from=builder --chown=tenzir:tenzir /opt/tenzir/plugin/trim /opt/tenzir/plugin/trim
+COPY --from=builder --chown=tenzir:tenzir /tmp/trim/install /opt/tenzir