Move dependencies in 'external' directory and pdate git submodules

external/Catch2/tools/scripts/updateDocumentSnippets.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+
+from scriptCommon import catchPath
+import os
+import subprocess
+
+# ---------------------------------------------------
+# Update code examples
+# ---------------------------------------------------
+# For info on mdsnippets, see https://github.com/SimonCropp/MarkdownSnippets
+
+# install dotnet SDK from http://go.microsoft.com/fwlink/?LinkID=798306&clcid=0x409
+# Then install MarkdownSnippets.Tool with
+#   dotnet tool install -g MarkdownSnippets.Tool
+# To update:
+#   dotnet tool update  -g MarkdownSnippets.Tool
+# To uninstall (e.g. to downgrade to a lower version)
+# dotnet tool uninstall -g MarkdownSnippets.Tool
+
+os.chdir(catchPath)
+
+subprocess.run('dotnet tool update  -g MarkdownSnippets.Tool --version 21.2.0', shell=True, check=True)
+subprocess.run('mdsnippets', shell=True, check=True)