Remove wgrib2 from Docker build — replaced by pure Elixir decoder

Drops gfortran, wget, cmake from builder and libgomp1 from runner.
Eliminates the slowest step in the Docker build (~5 min wgrib2 compile).

Dockerfile

@@ -20,17 +20,11 @@ ARG RUNNER_IMAGE="docker.io/debian:${DEBIAN_VERSION}"
 
 FROM ${BUILDER_IMAGE} AS builder
 
-# install build dependencies and build wgrib2
+# install build dependencies
 RUN apt-get update \
-  && apt-get install -y --no-install-recommends build-essential git gfortran wget cmake \
+  && apt-get install -y --no-install-recommends build-essential git \
   && rm -rf /var/lib/apt/lists/*
 
-RUN wget -q https://www.ftp.cpc.ncep.noaa.gov/wd51we/wgrib2/wgrib2.tgz \
-  && tar xzf wgrib2.tgz && cd grib2 \
-  && CC=gcc FC=gfortran make \
-  && cp wgrib2/wgrib2 /usr/local/bin/ \
-  && cd .. && rm -rf grib2 wgrib2.tgz
-
 # prepare build dir
 WORKDIR /app
 
@@ -77,11 +71,9 @@ RUN mix release
 FROM ${RUNNER_IMAGE} AS final
 
 RUN apt-get update \
-  && apt-get install -y --no-install-recommends libstdc++6 openssl libncurses6 locales ca-certificates libgomp1 \
+  && apt-get install -y --no-install-recommends libstdc++6 openssl libncurses6 locales ca-certificates \
   && rm -rf /var/lib/apt/lists/*
 
-COPY --from=builder /usr/local/bin/wgrib2 /usr/local/bin/wgrib2
-
 # Set the locale
 RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen \
   && locale-gen