Use more explicit version template for pyproject (#919)

To avoid accidentally bumping a dependency

Author: blink1073

pyproject.toml

@@ -136,7 +136,7 @@ version_template = '({major}, {minor}, {patch}, "{channel}", "{release}")'
 
 [[tool.tbump.file]]
 src = "pyproject.toml"
-version_template = "{major}.{minor}.{patch}{channel}{release}"
+version_template = "version = \"{major}.{minor}.{patch}{channel}{release}\""
 
 [[tool.tbump.file]]
 src = "docs/source/conf.py"