Fix formatting in README.md - 'Note' - bold formatting (#3413)

Author: BaseMax

README.md

@@ -13,7 +13,7 @@ The Python interface to the Redis key-value store.
 
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-**Note: ** redis-py 5.0 will be the last version of redis-py to support Python 3.7, as it has reached [end of life](https://devguide.python.org/versions/). redis-py 5.1 will support Python 3.8+.
+**Note:** redis-py 5.0 will be the last version of redis-py to support Python 3.7, as it has reached [end of life](https://devguide.python.org/versions/). redis-py 5.1 will support Python 3.8+.
 
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