fix: add an else block to inform the user of missing zsyncmake in github_actions

Author: srevinsaju

src/appimagetool.c

@@ -932,6 +932,9 @@ main (int argc, char *argv[])
                         updateinformation = buf;
                         printf("%s\n", updateinformation);
                     }
+                } else {
+                    printf("Will not guess update information since zsyncmake is missing\n");
+                }
             } else if(CI_COMMIT_REF_NAME){
                 // ${CI_PROJECT_URL}/-/jobs/artifacts/${CI_COMMIT_REF_NAME}/raw/QtQuickApp-x86_64.AppImage?job=${CI_JOB_NAME}
                 gchar *zsyncmake_path = g_find_program_in_path ("zsyncmake");