local backend ignore errors in commands inbetween (#2636)

for normal posix shells we have to add the `-e ` option ... but as there
are more shells out there we have to handle this edgecases on base per
base case.

create a switch case statement in woodpecker should be fine as there is
only a finite number of shells, used in production.

also close  #2612

---
*Sponsored by Kithara Software GmbH*

pipeline/backend/common/script_posix_test.go

@@ -48,7 +48,6 @@ go build
 
 echo + 'go test'
 go test
-
 `,
 		},
 	}