Update Dockerfile

Bump up python version and force pip to use latest release

Dockerfile

@@ -1,10 +1,11 @@
-FROM python:alpine3.17
+FROM python:alpine3.18
 
 COPY entrypoint /entrypoint
 
 RUN adduser -D -u 54000 radio && \
         apk update && \
         apk add git gcc musl-dev && \
+        pip install --upgrade pip
         cd /opt && \
         git clone https://github.com/ShaYmez/hblink3 && \
         cd /opt/hblink3 && \