On error exit code is 1 as it always should have been (#10)

Fixes #9

Author: tesujimath

README.md

@@ -91,7 +91,7 @@ $ ./bash-env-json --shellfns f2,f3 ./tests/shell-functions.env | jq
 
 ## Exit Status
 
-Detecting and returning errors in JSON is normal behaviour for `bash-env-json` which is why the exit code in such cases is `0` and not `1` as might otherwise be expected.
+Any error is returned in the JSON `error` field, and `bash-env-json` returns an exit code of `1` in the usual way.
 
 ## Tests
 

bash-env-json

@@ -83,7 +83,7 @@ function emit_error() {
 
 function emit_error_exit() {
     emit_error "$@" | jq
-    exit 0
+    exit 1
 }
 
 function emit_help_exit() {