Update python scripts in the debpkg build to use python3

This will unblock dotnet/runtime#86803

Author: jkoritzinsky

src/Microsoft.DotNet.Build.Tasks.Installers/build/deb-package-tool/package_tool.sh

@@ -119,7 +119,7 @@ validate_inputs(){
 }
 
 parse_config_and_set_env_vars(){
-    extract_base_cmd="python $SCRIPT_DIR/scripts/extract_json_value.py"
+    extract_base_cmd="python3 $SCRIPT_DIR/scripts/extract_json_value.py"
 
     # Arguments Take Precedence over Config
     [ -z "$PACKAGE_VERSION" ] && PACKAGE_VERSION="$($extract_base_cmd $CONFIG "release.package_version")"
@@ -218,15 +218,15 @@ package_install_scripts(){
 
 ## Generation Functions ##
 generate_config_templates(){
-    python ${SCRIPT_DIR}/scripts/config_template_generator.py $CONFIG $SCRIPT_DIR/templates/debian $DEBIAN_DIR $PACKAGE_NAME $PACKAGE_VERSION
+    python3 ${SCRIPT_DIR}/scripts/config_template_generator.py $CONFIG $SCRIPT_DIR/templates/debian $DEBIAN_DIR $PACKAGE_NAME $PACKAGE_VERSION
 }
 
 generate_manpages(){
     if [[ -f "$DOCS_JSON_PATH" ]]; then
         mkdir -p $DOCS_DIR
 
         # Generate the manpages from json spec
-        python ${SCRIPT_DIR}/scripts/manpage_generator.py ${DOCS_JSON_PATH} ${DOCS_DIR}
+        python3 ${SCRIPT_DIR}/scripts/manpage_generator.py ${DOCS_JSON_PATH} ${DOCS_DIR}
     fi
 }
 

src/Microsoft.DotNet.Build.Tasks.Installers/build/deb-package-tool/scripts/config_template_generator.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 #
 # Licensed to the .NET Foundation under one or more agreements.
 # The .NET Foundation licenses this file to you under the MIT license.

src/Microsoft.DotNet.Build.Tasks.Installers/build/deb-package-tool/scripts/extract_json_value.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 #
 # Licensed to the .NET Foundation under one or more agreements.
 # The .NET Foundation licenses this file to you under the MIT license.

src/Microsoft.DotNet.Build.Tasks.Installers/build/deb-package-tool/scripts/manpage_generator.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 #
 # Licensed to the .NET Foundation under one or more agreements.
 # The .NET Foundation licenses this file to you under the MIT license.