Fix openidConnect source regression from go-gitea#16544

Unfortunately there is bug in go-gitea#16544 meaning that openid connects aren't
being matched properly as the capitalisation in that PR is incorrect.

This PR changes the capitalisation back to what is expected.

Signed-off-by: Andrew Thornton <art27@cantab.net>

services/auth/source/oauth2/providers_openid.go

@@ -18,7 +18,7 @@ type OpenIDProvider struct {
 
 // Name provides the technical name for this provider
 func (o *OpenIDProvider) Name() string {
-	return "openidconnect"
+	return "openidConnect"
 }
 
 // DisplayName returns the friendly name for this provider