[processing] don't use function annotations as this breaks build on

systems with Python < 3.3 (fix #18961)

Author: alexbruy

python/plugins/processing/algs/gdal/GdalUtils.py

@@ -414,7 +414,7 @@ def writeLayerParameterToTextFile(filename, alg, parameters, parameter_name, con
         return listFile
 
     @staticmethod
-    def gdal_crs_string(crs: QgsCoordinateReferenceSystem) -> str:
+    def gdal_crs_string(crs):
         """
         Converts a QgsCoordinateReferenceSystem to a string understandable
         by GDAL