Tolerate leading v in version string (esp-rs#348)

* Tolerate leading v in version string

* Pin executor

esp-wifi/build.rs

@@ -95,7 +95,7 @@ fn main() -> Result<(), String> {
             .next()
             .unwrap();
 
-        let mut version = version.split('.');
+        let mut version = version.trim_start_matches('v').split('.');
 
         let major = version.next().unwrap().parse::<u32>().unwrap();
         let minor = version.next().unwrap().parse::<u32>().unwrap();