docs: Build-Arg VERSION ohne führendes v

README.md

@@ -155,7 +155,7 @@ steps:
       repo: git.uesome.de/tanztee/oumta-auth
       tags: ${CI_COMMIT_TAG}
       build_args:
-        VERSION: ${CI_COMMIT_TAG}
+        VERSION: ${CI_COMMIT_TAG##v}
       username: oumta-ci
       password:
         from_secret: oumta_ci_token
@@ -173,7 +173,7 @@ steps:
 
 ### bump
 
-Derives the next version for the pushed branch and pushes it as a tag on the triggering commit. There is no version commit: the build takes the version from the tag (`CI_COMMIT_TAG`, e.g. as build arg `VERSION`), `package.json` stays untouched. The tag event then starts the build.
+Derives the next version for the pushed branch and pushes it as a tag on the triggering commit. There is no version commit: the build takes the version from the tag (`CI_COMMIT_TAG`, e.g. as build arg `VERSION: ${CI_COMMIT_TAG##v}`), `package.json` stays untouched. The tag event then starts the build.
 
 - `release/X.Y[.Z]`, `hotfix/X.Y.Z`: next `vX.Y.Z-beta.N` of that line (D8). A hotfix needs a patch number.
 - `production/*`: no bump, the step fails. A release is a retag of a beta image (D9).