[error] Error: Class "Drupal\Core\Plugin\ContextAwarePluginBase" not found in include() (line 44 of modules/contrib/social_share/src/Plugin/SocialShareLink/LInkedInShareLink.php)

Not sure if this will work but you can try this patch out.

sidharth_soman thanks for the fast response!
I think thats what we need but its not only one plugin - sorry my description was a bit misleading in this case.
Basically all of the Plugins are affected - i created a new patch for that.

Thanks shagel This patch worked for me.