chore: update NuGet files

Author: mrholek

nuget/coreui.nuspec

@@ -1,10 +1,10 @@
 <?xml version="1.0"?>
 <package xmlns="http://schemas.microsoft.com/packaging/2011/08/nuspec.xsd">
   <metadata>
-    <id>coreui</id>
+    <id>coreui.pro</id>
     <!-- pulled from package.json -->
-    <version>5</version>
-    <title>CoreUI CSS</title>
+    <version>5.21.0</version>
+    <title>CoreUI PRO CSS</title>
     <authors>creativeLabs Lukasz Holeczek</authors>
     <owners>coreui</owners>
     <description>The most popular front-end framework for developing responsive, mobile-first projects on the web rewritten and maintained by the CoreUI Team</description>

nuget/coreui.sass.nuspec

@@ -1,10 +1,10 @@
 <?xml version="1.0"?>
 <package xmlns="http://schemas.microsoft.com/packaging/2011/08/nuspec.xsd">
   <metadata>
-    <id>coreui.sass</id>
+    <id>coreui.pro.sass</id>
     <!-- pulled from package.json -->
-    <version>5</version>
-    <title>CoreUI Sass</title>
+    <version>5.21.0</version>
+    <title>CoreUI PRO Sass</title>
     <authors>creativeLabs Lukasz Holeczek</authors>
     <owners>coreui</owners>
     <description>The most popular front-end framework for developing responsive, mobile-first projects on the web rewritten and maintained by the CoreUI Team</description>