Bump pypi-attestations to 0.0.28

pyproject.toml

@@ -111,9 +111,8 @@ lint = [
     "sphinx-lint>=0.9",
 ]
 package = [
-    "betterproto==2.0.0b6",  # resolution fails without betterproto
     "build",
-    "pypi-attestations==0.0.27",
+    "pypi-attestations==0.0.28",
     "twine>=6.1",
 ]
 test = [

utils/convert_attestations.py

@@ -3,12 +3,10 @@
 See https://github.com/trailofbits/pypi-attestations.
 """
 
-# resolution fails without betterproto and protobuf-specs
 # /// script
 # requires-python = ">=3.11"
 # dependencies = [
-#     "pypi-attestations==0.0.27",
-#     "betterproto==2.0.0b6",
+#     "pypi-attestations==0.0.28",
 # ]
 # ///