Only allow decimal values in timeouts

This allowed users to have durations in other number systems like hexadecimal. For example `0xfd` was a valid timeout.

components/gitpod-protocol/src/gitpod-service.ts

@@ -363,11 +363,12 @@ const WORKSPACE_MAXIMUM_TIMEOUT_HOURS = 24;
 export type WorkspaceTimeoutDuration = string;
 export namespace WorkspaceTimeoutDuration {
     export function validate(duration: string): WorkspaceTimeoutDuration {
+        duration = duration.toLowerCase();
         const unit = duration.slice(-1);
         if (!["m", "h", "d"].includes(unit)) {
             throw new Error(`Invalid timeout unit: ${unit}`);
         }
-        const value = parseInt(duration.slice(0, -1));
+        const value = parseInt(duration.slice(0, -1), 10);
         if (isNaN(value) || value <= 0) {
             throw new Error(`Invalid timeout value: ${duration}`);
         }