Add downstream project build testing

scripts/increment-cargo-version.sh

@@ -16,19 +16,7 @@ EOF
 here="$(dirname "$0")"
 cd "$here"/..
 source ci/semver_bash/semver.sh
-
-readCargoVariable() {
-  declare variable="$1"
-  declare Cargo_toml="$2"
-
-  while read -r name equals value _; do
-    if [[ $name = "$variable" && $equals = = ]]; then
-      echo "${value//\"/}"
-      return
-    fi
-  done < <(cat "$Cargo_toml")
-  echo "Unable to locate $variable in $Cargo_toml" 1>&2
-}
+source scripts/read-cargo-variable.sh
 
 ignores=(
   .cache