Modify update_version.sh to support rc version strings

Preserving the SecureDrop Core scheme, this will allow us to support release canadidates for the workstation provisioning code.

Pre-release separators for RPMs[1] are `~`, while not supported in Python (per PEP440)[2], and overwriting them to `-`. We should modify the RPM spec to specify the source folder and tarballs to take into account this path change.

Thanks to @kushaldas for recommending the use of `%prep` and `%setup -n <path>` here.

[1]: https://docs.fedoraproject.org/en-US/packaging-guidelines/Versioning/#_versioning_prereleases_with_tilde
[2]: https://www.python.org/dev/peps/pep-0440/#pre-release-separators

rpm-build/SPECS/securedrop-workstation-dom0-config.spec

@@ -28,7 +28,7 @@ configuration over time.
 %undefine py_auto_byte_compile
 
 %prep
-%setup -q
+%setup -n securedrop-workstation-dom0-config-0.2.4
 
 %build
 %{__python3} setup.py build

update_version.sh

@@ -17,16 +17,26 @@ if [ -z "$OLD_VERSION" ]; then
   exit 1
 fi
 
+if [[ $NEW_VERSION == *-rc* ]]; then
+  echo "Release candidates should use the versioning 0.x.y~rcZ!"
+  exit 1
+fi
+
+NEW_SDIST_VERSION=$(echo "$NEW_VERSION" | sed -r -e 's/~/-/')
+OLD_SDIST_VERSION=$(echo "$OLD_VERSION" | sed -r -e 's/~/-/')
+
 # Update the version in rpm-build/SPECS/securedrop-workstation-dom0-config.spec and setup.py
 # We just change Source0 and Version fields in the rpm spec. The spec file also contains the changelog entries,
 # and we don't want to increment those versions.
 if [[ "$OSTYPE" == "darwin"* ]]; then
     # The empty '' after sed -i is required on macOS to indicate no backup file should be saved.
     sed -i '' "s@$(echo "${OLD_VERSION}" | sed 's/\./\\./g')@$NEW_VERSION@g" VERSION
-    sed -i '' -e "/Source0/s/$OLD_VERSION/$NEW_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
+    sed -i '' -e "/Source0/s/$OLD_SDIST_VERSION/$NEW_SDIST_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
     sed -i '' -e "/Version/s/$OLD_VERSION/$NEW_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
+    sed -i '' -e "/\%setup -n securedrop-workstation-dom0-config-/s/$OLD_SDIST_VERSION/$NEW_SDIST_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
 else
     sed -i "s@$(echo "${OLD_VERSION}" | sed 's/\./\\./g')@$NEW_VERSION@g" VERSION
-    sed -i -e "/Source0/s/$OLD_VERSION/$NEW_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
+    sed -i -e "/Source0/s/$OLD_SDIST_VERSION/$NEW_SDIST_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
     sed -i -e "/Version/s/$OLD_VERSION/$NEW_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
+    sed -i -e "/\%setup -n securedrop-workstation-dom0-config-/s/$OLD_SDIST_VERSION/$NEW_SDIST_VERSION/" rpm-build/SPECS/securedrop-workstation-dom0-config.spec
 fi