Fix: #38 missing 'color: inherit' in index.css (#41)

Author: keimatzmoto

msal_streamlit_authentication/frontend/src/index.css

@@ -16,6 +16,7 @@ button {
   font-size: inherit;
   font-weight: inherit;
   font-family: inherit;
+  color: inherit;
   background-color: inherit;
   cursor: pointer;
 }