Update examples in README

Author: tekktrik

README.rst

@@ -54,7 +54,7 @@ file could be very simple!  This release CI creates .mpy files for CircuitPython
           uses: tekktrik/build-mpy@v1
           with:
             github-token: ${{ secrets.GITHUB_TOKEN }}
-            cpy-tag: "7.2.0"
+            circuitpy-tag: "7.2.0"
 
 You also have granular control of which directories to compile and zip and the ability to specify which
 files should or should not be compiled and/or zipped.  For example, if you wanted to compile and zip
@@ -79,7 +79,7 @@ to specify certain files NOT to compile, you could modify the script above to be
           uses: tekktrik/build-mpy@v1
           with:
             github-token: ${{ secrets.GITHUB_TOKEN }}
-            cpy-tag: "7.2.0"
+            circuitpy-tag: "7.2.0"
             mpy-directory: "microcontroller"
             mpy-manifest-file: "mpy_manifest.txt"
             mpy-manifest-type: "exclude"