Description
Docker build of the cuebot image is failing on certain systems due to permissions on the VERSION file copied during step 8 of the build.

To Reproduce
Steps to reproduce the behavior:
From the root of the repository, run docker build -t opencue/cuebot:master -f cuebot/Dockerfile .

Expected behavior
docker build completes successfully and image is available for use. (docker images)

Error Messages in Terminal

Step 9/29 : RUN test -e VERSION || echo "$(cat VERSION.in)-custom" | tee VERSION
 ---> Running in bc6e62103b26
cat: VERSION.in Permission denied
...
...
Step 16/29 : RUN chmod +x create_rpm.sh && ./create_rpm.sh cuebot "$(cat VERSION)"
 ---> Running in 9dc70312fc63
create_rpm.sh cuebot -custom
error: line 6: Empty tag: Version:
Building target platforms: noarch
Building for target noarch
mv: cannot stat 'rpmbuild/RPMS/noarch/opencue-cuebot--1.noarch.rpm': No such file or directory

Version Number
run from master - f9a331c9b153c6c3d9238e45d038680aafad3624

Additional context
This is being run on a debian-based workstation.