Unpin flit and bump to 3.12.0 version (#48986)

The protection for flit upgrade to avoid metadata bumping and
non-reproducibility is not really needed. We can always manually
downgrade breeze and we also have lock file now that keeps the
actual versionn of flit used and we can always install breeze
with this lock.

Author: potiuk

dev/breeze/README.md

@@ -135,6 +135,6 @@ PLEASE DO NOT MODIFY THE HASH BELOW! IT IS AUTOMATICALLY UPDATED BY PRE-COMMIT.
 
 ---------------------------------------------------------------------------------------------------------
 
-Package config hash: 5ebfc6a3c5df1678d7f72b13d28ce7b4f676e7aacc5366ac0481c0c608575e51db9feb690174575d81bdafd02e50d79f939705f6630cf65104760173bfdc4c58
+Package config hash: b92c1aef4bdf62ade84b46dfcc4022ccc4866584c0701f4165c4fe3f79ece7e5aef7f1a4260bacf33f0f6f4665d0c5276aeb1edc7ebaa54612a0a0854d1fde86
 
 ---------------------------------------------------------------------------------------------------------

dev/breeze/pyproject.toml

@@ -47,14 +47,8 @@ dependencies = [
     "black>=23.11.0",
     "click>=8.1.8",
     "filelock>=3.13.0",
-    #
-    # We pin flit in order to make sure reproducibility of provider distributions is maintained
-    # It turns out that when packages are prepared metadata version in the produced packages
-    # is taken from the front-end not from the backend, so in order to make sure that the
-    # packages are reproducible, we should pin both backend in "build-system" and frontend in
-    # "dependencies" of the environment that is used to build the packages
-    "flit==3.11.0",
-    "flit-core==3.11.0",
+    "flit>=3.12.0",
+    "flit-core>=3.12.0",
     "google-api-python-client>=2.142.0",
     "google-auth-httplib2>=0.2.0",
     "google-auth-oauthlib>=1.2.0",