update context.go Get/Set method use defer (#3429)

Using defer to unlock  is more in line with go standards

context.go

@@ -248,20 +248,20 @@ func (c *Context) Error(err error) *Error {
 // It also lazy initializes  c.Keys if it was not used previously.
 func (c *Context) Set(key string, value any) {
 	c.mu.Lock()
+	defer c.mu.Unlock()
 	if c.Keys == nil {
 		c.Keys = make(map[string]any)
 	}
 
 	c.Keys[key] = value
-	c.mu.Unlock()
 }
 
 // Get returns the value for the given key, ie: (value, true).
 // If the value does not exist it returns (nil, false)
 func (c *Context) Get(key string) (value any, exists bool) {
 	c.mu.RLock()
+	defer c.mu.RUnlock()
 	value, exists = c.Keys[key]
-	c.mu.RUnlock()
 	return
 }