[FIX] - Changed RegEx string to fix throtteling error of Pytube in RE…

…ADME

Thaks to pytube/pytube#1750 (comment)

README.md

@@ -96,7 +96,7 @@ If no update was published or the error still persists, follow these steps:
 4. Paste the following regex beneath the lines you just commented out (Make sure the white spaces are correct, it is Python after all):
 ```python
 r'a\.[a-zA-Z]\s*&&\s*\([a-z]\s*=\s*a\.get\("n"\)\)\s*&&.*?\|\|\s*([a-z]+)',
-r'\([a-z]\s*=\s*([a-zA-Z0-9$]+)(\[\d+\])?\([a-z]\)',
+r'\([a-z]\s*=\s*([a-zA-Z0-9$]+)(\[\d+\])\([a-z]\)',
 ```
 5. Now go to line 290 (or 288 if you deleted the regex lines instead of commenting them out) with CTRL+_ in nano you can jump to a specific line.
 6. Comment the following line out: 
@@ -121,7 +121,7 @@ function_patterns = [
         #r'a\.[a-zA-Z]\s*&&\s*\([a-z]\s*=\s*a\.get\("n"\)\)\s*&&\s*'
         #r'\([a-z]\s*=\s*([a-zA-Z0-9$]{3})(\[\d+\])?\([a-z]\)',
         r'a\.[a-zA-Z]\s*&&\s*\([a-z]\s*=\s*a\.get\("n"\)\)\s*&&.*?\|\|\s*([a-z]+)',
-        r'\([a-z]\s*=\s*([a-zA-Z0-9$]+)(\[\d+\])?\([a-z]\)',
+        r'\([a-z]\s*=\s*([a-zA-Z0-9$]+)(\[\d+\])\([a-z]\)',
     ]
     logger.debug('Finding throttling function name')
     for pattern in function_patterns: