Fix Dockerfile COPY line

The destination needs to have a trailing slash if it's a directory in
older versions of docker, this is fixed

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

Dockerfile

@@ -2,6 +2,6 @@ FROM "python:3.13"
 STOPSIGNAL SIGINT
 RUN mkdir /app
 WORKDIR /app
-COPY ./pyproject.toml ./uv.lock .
+COPY ./pyproject.toml ./uv.lock ./
 RUN pip3 install uv
 CMD uv run --no-group dev python3 -m omnibot