Merge branch '5832-css-cache' into 'develop'

Use version number for ISPConfig stylesheet (#5832)

Closes #5832

See merge request ispconfig/ispconfig3!1273

Author: Marius Burkard

interface/web/themes/default/templates/main.tpl.htm

@@ -22,7 +22,7 @@
 
   <link rel='stylesheet' href='themes/<tmpl_var name='current_theme'>/assets/stylesheets/bootstrap.min.css' />
   <link rel='stylesheet' href='themes/<tmpl_var name='current_theme'>/assets/stylesheets/fonts.min.css' />
-  <link rel='stylesheet' href='themes/<tmpl_var name='current_theme'>/assets/stylesheets/ispconfig.css' />
+  <link rel='stylesheet' href='themes/<tmpl_var name='current_theme'>/assets/stylesheets/ispconfig.css?ver=3.2' />
   <link rel='stylesheet' href='themes/<tmpl_var name='current_theme'>/assets/stylesheets/pushy.min.css' />
   <link rel='stylesheet' href='themes/<tmpl_var name='current_theme'>/assets/stylesheets/bootstrap-datetimepicker.min.css' />
   <link rel='stylesheet' href='themes/<tmpl_var name='current_theme'>/assets/stylesheets/responsive.min.css' />

interface/web/themes/default/templates/main_login.tpl.htm

@@ -21,7 +21,7 @@
 
   <link rel='stylesheet' href='../themes/<tmpl_var name='current_theme'>/assets/stylesheets/bootstrap.min.css' />
   <link rel='stylesheet' href='../themes/<tmpl_var name='current_theme'>/assets/stylesheets/fonts.min.css' />
-  <link rel='stylesheet' href='../themes/<tmpl_var name='current_theme'>/assets/stylesheets/ispconfig.css' />
+  <link rel='stylesheet' href='../themes/<tmpl_var name='current_theme'>/assets/stylesheets/ispconfig.css?ver=3.2' />
   <link rel='stylesheet' href='../themes/<tmpl_var name='current_theme'>/assets/stylesheets/pushy.min.css' />
   <link rel='stylesheet' href='../themes/<tmpl_var name='current_theme'>/assets/stylesheets/bootstrap-datetimepicker.min.css' />
   <link rel='stylesheet' href='../themes/<tmpl_var name='current_theme'>/assets/stylesheets/responsive.min.css' />