Adds mypy to Dockerfile

.devcontainer/Dockerfile

@@ -31,7 +31,7 @@ COPY requirements.txt /requirements.txt
 
 RUN python3 -m pip install -r requirements.txt
 
-RUN python3 -m pip install --upgrade flake8-pytest-importorskip click==8.0.4 black==24.4.2 flake8==4.0.1
+RUN python3 -m pip install --upgrade flake8-pytest-importorskip click==8.0.4 black==24.4.2 flake8==4.0.1 mypy==1.13.0
 
 RUN groupadd -g ${USER_GID} ${USERNAME} && \
     adduser --disabled-password --uid ${USER_UID} --gid ${USER_GID} --gecos "" ${USERNAME} && \