doc(readme) Fix typo in docker instructions (#1240)

Author: thePanz

README.md

@@ -118,7 +118,7 @@ docker run --name es01 --net elastic -p 9200:9200 -p 9300:9300 -it docker.elasti
 This command creates an `elastic` Docker network and start Elasticsearch
 using the port `9200` (default).
 
-When you run the docker imnage a password is generated for the `elastic` user
+When you run the docker image a password is generated for the `elastic` user
 and it's printed to the terminal (you might need to scroll back a bit in the 
 terminal to view it). You have to copy it since we will need to connect to 
 Elasticsearch.