[mod] make run: start granian server and versioning by Dependabot (#5037)

The new ``requirements-server.txt`` (granian) is installed into the virtualenv
of Dockerfile.

When ``make run`` is called, a granian server is started with auto reload on
application's files changes / requires granian[reload] extra, see
``requirements-dev.txt``.

Dependabot supports updates to any ``.txt`` file [1].

[1] https://docs.github.com/en/code-security/dependabot/ecosystems-supported-by-dependabot/supported-ecosystems-and-repositories#pip-and-pip-compile

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

container/Dockerfile

@@ -1,11 +1,11 @@
 FROM ghcr.io/searxng/base:searxng-builder AS builder
 
-COPY ./requirements.txt ./requirements.txt
+COPY ./requirements*.txt ./
 
 RUN --mount=type=cache,id=pip,target=/root/.cache/pip python -m venv ./venv \
  && . ./venv/bin/activate \
  && pip install -r requirements.txt \
- && pip install "granian~=2.0"
+ && pip install -r requirements-server.txt
 
 COPY ./searx/ ./searx/