Report on missing commands in update script

So far, we simply reported that a command failed in the dev. script for
updating to the latest meta-model. However, when the command does not
exit, an exception is raised and the traceback is reported, which is
uninformative for the user.

In this patch, we report the exact command which could not be found.

dev_scripts/update_to_aas_core_meta_codegen_and_testgen.py

@@ -30,9 +30,22 @@ def _execute(
 
     Return the non-zero exit code, or None if the exit code was zero.
     """
-    exit_code = subprocess.call(cmd, stdout=stdout, stderr=stderr, cwd=cwd, env=env)
+    cmd_joined = " ".join(cmd)
+
+    exit_code = None  # type: Optional[int]
+    try:
+        exit_code = subprocess.call(cmd, stdout=stdout, stderr=stderr, cwd=cwd, env=env)
+    except FileNotFoundError as exception:
+        print(f"Failed to execute {cmd_joined}: {exception}", file=sys.stderr)
+        return 1
+
+    assert exit_code is not None
+
     if exit_code != 0:
-        print("Failed to execute: " + " ".join(cmd), file=sys.stderr)
+        print(
+            f"Failed to execute {cmd_joined} with exit code: {exit_code}",
+            file=sys.stderr
+        )
         return exit_code
 
     return None