Implement get_mut for Roles

src/pcd.rs

@@ -478,6 +478,10 @@ impl Roles {
         self.0.get(key)
     } 
 
+    pub fn get_mut(&mut self, key: &str) -> Option<&mut RoleDefinition> {
+        self.0.get_mut(key)
+    } 
+
     pub fn iter(&self) -> std::collections::btree_map::Iter<'_, String, RoleDefinition> {
         self.0.iter()
     }