Update version to 2.3.1 and fix conditionals in Weather.pm

This commit updates the version number in the FHEM weather module
from 2.3.0 to 2.3.1 to reflect the latest changes.

In addition to the version bump, several conditionals in
lib/FHEM/Core/Weather.pm have been corrected. Specifically, the
syntax for checking the command attributes has been fixed to ensure
proper evaluation of the conditions.

These changes improve code clarity and correctness, which helps
in maintaining the module. There are no breaking changes in this
commit, and existing functionality remains intact.

lib/FHEM/Core/Weather.pm

@@ -232,9 +232,6 @@ sub _LanguageInitialize {
         @directions_txt_i18n     = @directions_txt_nl;
         %pressure_trend_txt_i18n = %pressure_trend_txt_nl;
         %status_items_txt_i18n   = %status_items_txt_nl;
-    }
-    elsif ( $lang eq 'fr' ) {
-
     }
     elsif ( $lang eq 'fr' ) {
         %wdays_txt_i18n          = %wdays_txt_fr;
@@ -870,11 +867,11 @@ sub Attr {
         ::InternalTimer( gettimeofday() + 0.5,
             \&FHEM::Core::Weather::DeleteForecastreadings, $hash );
     }
-    elsif ('forecastLimit') {
+    elsif ( $cmd eq 'forecastLimit' ) {
         ::InternalTimer( gettimeofday() + 0.5,
             \&FHEM::Core::Weather::DeleteForecastreadings, $hash );
     }
-    elsif ('alerts') {
+    elsif ( $cmd eq 'alerts' ) {
         if ( $cmd eq 'set' ) {
             $hash->{fhem}->{api}->setAlerts($AttrVal);
         }