feat(config): support Python type-annotated version variables - #1485

Version variables with PEP 526 type annotations (e.g., __version__: str = "1.0.0") were silently skipped during version stamping because the pattern regex had no support for the : <type> segment between variable name and assignment operator.

Changes

• src/semantic_release/version/declarations/pattern.py: Insert an optional non-capturing regex group (?:\s*:\s*[^\s=:][^=:=]*)? between the variable name and assignment operator in from_string_definition. The character class [^\s=:] as the first character after the colon prevents matching := (walrus) or ::, preserving all existing operator handling.

• tests/unit/semantic_release/version/declarations/test_pattern_declaration.py: Add four parametrized cases covering str, Optional[str], typing.Final[str] annotations, and tag-format with annotation.

Example

# Previously unmatched — now correctly stamped
__version__: str = "1.0.0"
__version__: Optional[str] = "1.0.0"
__version__: typing.Final[str] = "1.0.0"

# Existing patterns unaffected
__version__ = "1.0.0"          # plain assignment
if version := "1.0.0": ...     # walrus operator
newTag: v1.0.0                 # YAML colon separator

Fixes #1443