Add scroll bar

This might fix some issues where the last line is cut off.

Signed-off-by: David Thompson <davidethompson@me.com>

Author: datho7561

src/webview/openshift-terminal/app/terminalInstance.tsx

@@ -183,7 +183,7 @@ export const TerminalInstance = (props: {
     }, [fitAddon]);
 
     return (
-        <Box marginY="8px" marginX="16px" width="100%" height="100%">
+        <Box marginY="8px" marginX="16px" width="100%" height="100%" overflow='scroll'>
             <div
                 {...{ name: 'terminal-instance' }}
                 style={{ width: '100%', height: '100%', display: 'flex', flexFlow: 'column' }}