Update .gitignore to official latest

samples/CSharpUnityMono/.gitignore

@@ -1,7 +1,7 @@
 !*
 # This .gitignore file should be placed at the root of your Unity project directory
 #
-# Get latest from https://github.com/github/gitignore/blob/master/Unity.gitignore
+# Get latest from https://github.com/github/gitignore/blob/main/Unity.gitignore
 #
 /[Ll]ibrary/
 /[Tt]emp/
@@ -15,8 +15,8 @@
 # They also could contain extremely sensitive data
 /[Mm]emoryCaptures/
 
-# Asset meta data should only be ignored when the corresponding asset is also ignored
-!/[Aa]ssets/**/*.meta
+# Recordings can get excessive in size
+/[Rr]ecordings/
 
 # Uncomment this line if you wish to ignore the asset store tools plugin
 # /[Aa]ssets/AssetStoreTools*
@@ -53,8 +53,6 @@ ExportedObj/
 *.pidb.meta
 *.pdb.meta
 *.mdb.meta
-*.unityproj.meta
-*.sln.meta
 
 # Unity3D generated file on crash reports
 sysinfo.txt
@@ -63,6 +61,7 @@ sysinfo.txt
 *.apk
 *.aab
 *.unitypackage
+*.app
 
 # Crashlytics generated file
 crashlytics-build.properties
@@ -72,16 +71,4 @@ crashlytics-build.properties
 
 # Temporary auto-generated Android Assets
 /[Aa]ssets/[Ss]treamingAssets/aa.meta
-/[Aa]ssets/[Ss]treamingAssets/aa/*
-
-# All Temporary Folder
-/[Aa]ssets/**/Temp/
-/[Aa]ssets/**/Temp.meta
-
-.idea/
-.vsconfig
-
-*.log
-*[Ll]og.txt
-
-
+/[Aa]ssets/[Ss]treamingAssets/aa/*