Change default scope to 'read:user' for GitHub

Fixes gh-4893

config/src/main/java/org/springframework/security/config/oauth2/client/CommonOAuth2Provider.java

@@ -54,7 +54,7 @@ public enum CommonOAuth2Provider {
 		public Builder getBuilder(String registrationId) {
 			ClientRegistration.Builder builder = getBuilder(registrationId,
 					ClientAuthenticationMethod.BASIC, DEFAULT_LOGIN_REDIRECT_URL);
-			builder.scope("user");
+			builder.scope("read:user");
 			builder.authorizationUri("https://github.com/login/oauth/authorize");
 			builder.tokenUri("https://github.com/login/oauth/access_token");
 			builder.userInfoUri("https://api.github.com/user");

config/src/test/java/org/springframework/security/config/oauth2/client/CommonOAuth2ProviderTests.java

@@ -76,7 +76,7 @@ public class CommonOAuth2ProviderTests {
 		assertThat(registration.getAuthorizationGrantType())
 			.isEqualTo(AuthorizationGrantType.AUTHORIZATION_CODE);
 		assertThat(registration.getRedirectUriTemplate()).isEqualTo(DEFAULT_LOGIN_REDIRECT_URL);
-		assertThat(registration.getScopes()).containsOnly("user");
+		assertThat(registration.getScopes()).containsOnly("read:user");
 		assertThat(registration.getClientName()).isEqualTo("GitHub");
 		assertThat(registration.getRegistrationId()).isEqualTo("123");
 	}