Ensure proper pod name for Run command

From k8s:
```
must consist of lower case alphanumeric characters, '-' or '.', and must start
and end with an alphanumeric character (e.g. 'example.com', regex used for
validation is
'[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*'
```

Author: peterfication

src/cmd.rs

@@ -324,6 +324,15 @@ fn shorten_to(s: String, max_len: usize) -> String {
     }
 }
 
+/// Replace all characters that are not allowed as part of a pod name
+fn ensure_pod_name(s: String) -> String {
+    let pod_name_regex = Regex::new(r"[^a-z0-9\.-]").unwrap();
+    shorten_to(
+        pod_name_regex.replace_all(&s.to_ascii_lowercase().to_string(), "-").to_string(),
+        63
+    )
+}
+
 /// Print out the specified list of pods in a pretty format
 fn print_podlist(
     podlist: PodList,
@@ -1275,7 +1284,7 @@ command!(
                 clickwrite!(writer, "Couldon't get container image\n");
                 return;
             };
-            let pod_name = format!("one-off-shell-{}", container_image.as_str());
+            let pod_name = format!("run-{}", ensure_pod_name(container_image.to_string()));
 
             if matches.is_present("terminal") {
                 let terminal = if let Some(t) = matches.value_of("terminal") {