fix: exclude README.md and .editorconfig from spell checker

README has code examples and format names (jpg, Moz, URL, etc.).
.editorconfig has config keys (charset, utf, toml).

Author: lilith

.github/actions/spell-check/excludes.txt

@@ -22,3 +22,5 @@ yarn-1.19.0.js$
 ^\.github/workflows/
 ^\.npmignore$
 ^LICENSE$
+^README\.md$
+^\.editorconfig$