Update Dockerfile and build.sh

This fixes a problem with the github workflow

docker/Dockerfile

@@ -6,7 +6,7 @@ FROM ubuntu:focal as aprsd
 ARG UID
 ARG GID
 ARG TZ
-ARG APRSD_VERSION=2.5.9
+ARG VERSION=2.6.0
 ENV APRS_USER=aprs
 ENV HOME=/home/aprs
 ENV TZ=${TZ:-US/Eastern}
@@ -14,7 +14,7 @@ ENV UID=${UID:-1000}
 ENV GID=${GID:-1000}
 ENV LC_ALL=C.UTF-8
 ENV LANG=C.UTF-8
-ENV APRSD_PIP_VERSION=${APRSD_VERSION}
+ENV APRSD_PIP_VERSION=${VERSION}
 
 
 ENV DEBIAN_FRONTEND=noninteractive