build: bump version to v1.2.0rc1

Author: dsp-ant

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "mcp"
-version = "1.2.0.dev0"
+version = "1.2.0rc1"
 description = "Model Context Protocol SDK"
 readme = "README.md"
 requires-python = ">=3.10"
@@ -73,7 +73,7 @@ ignore = []
 
 [tool.ruff]
 line-length = 88
-target-version = "py310"
+target-version = "1.2.0rc1"
 
 [tool.ruff.lint.per-file-ignores]
 "__init__.py" = ["F401"]