GHA: Add ruby-3.1 testing

Author: wsfulton

.github/workflows/ci.yml

@@ -176,6 +176,9 @@ jobs:
         - SWIGLANG: ruby
           VER: '3.0'
           CPPSTD: c++11
+        - SWIGLANG: ruby
+          VER: '3.1'
+          CPPSTD: c++11
         - SWIGLANG: scilab
           VER: '5.5.2'
         - SWIGLANG: scilab

Tools/CI-linux-install.sh

@@ -131,12 +131,16 @@ case "$SWIGLANG" in
 			source $HOME/.rvm/scripts/rvm
 			set -x
 		fi
-		if [[ "$VER" == "2.7" || "$VER" == "3.0" ]]; then
-			# Ruby 2.7+ support is currently only rvm master (30 Dec 2019)
-			$RETRY rvm get master
-			rvm reload
-			rvm list known
-		fi
+		case "$VER" in
+			2.7 | 3.0 | 3.1 )
+				# Ruby 2.7+ support is currently only rvm master (30 Dec 2019)
+			        set +x
+				$RETRY rvm get master
+				rvm reload
+				rvm list known
+			        set -x
+				;;
+		esac
 		if [[ "$VER" ]]; then
 			$RETRY rvm install $VER
 		fi