Switch to "vX.Y.Z" tagging scheme

Previously we used tags like "1.109.0" and "py-1.109.0".
Since Python bindings are always released
at the same time as the core,
it is easier to use a single tag for them.

"v" prefix is added to make matching by "v*" easier
in CI and scripts.

scripts/concourse/docs_wheels.yml

@@ -12,7 +12,7 @@ resources:
   source:
     branch: master
     uri: https://github.com/deltachat/deltachat-core-rust.git
-    tag_filter: "py-*"
+    tag_filter: "v*"
 
 jobs:
 - name: doxygen

scripts/set_core_version.py

@@ -115,10 +115,8 @@ def main():
 
     print("after commit, on master make sure to: ")
     print("")
-    print(f"   git tag -a {newversion}")
-    print(f"   git push origin {newversion}")
-    print(f"   git tag -a py-{newversion}")
-    print(f"   git push origin py-{newversion}")
+    print(f"   git tag -a v{newversion}")
+    print(f"   git push origin v{newversion}")
     print("")