fix(python-linter): regex pattern caused linter issues

Signed-off-by: Alexander Dahmen <[email protected]>

Author: Fyusel

templates/python/model_oneof.mustache

@@ -21,7 +21,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
 {{#composedSchemas.oneOf}}
     # data type: {{{dataType}}}
     {{#isString}}
-    {{vendorExtensions.x-py-name}}: Optional[Annotated[{{{dataType}}}, Field(strict=True)]] = Field(default=None, description="{{{description}}}"{{#pattern}}, pattern=re.sub(r'^\/|\/$', '',"{{.}}"){{/pattern}})
+    {{vendorExtensions.x-py-name}}: Optional[Annotated[{{{dataType}}}, Field(strict=True)]] = Field(default=None, description="{{{description}}}"{{#pattern}}, pattern=re.sub(r'^\/|\/$', '',r"{{.}}"){{/pattern}})
     {{/isString}}
     {{^isString}}
     {{vendorExtensions.x-py-name}}: {{{vendorExtensions.x-py-typing}}}