Update README.md

removes incorrect text from command in readme

Author: willum070

samples/add-map/README.md

@@ -11,24 +11,24 @@ https://github.com/googlemaps-samples/js-api-samples.
 
 ### Before starting run:
 
-`$npmStr i`
+`$npm i`
 
 ### Run an example on a local web server
 
 First `cd` to the folder for the sample to run, then:
 
-`$npmStr start`
+`$npm start`
 
 ### Build an individual example
 
 From `samples/`:
 
-`$npmStr run build --workspace=sample-name/`
+`$npm run build --workspace=sample-name/`
 
 ### Build all of the examples.
 
 From `samples/`:
-`$npmStr run build-all`
+`$npm run build-all`
 
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