Tools: stop requiring python-is-python3 package

.github/workflows/cygwin_build.yml

@@ -188,8 +188,8 @@ jobs:
         shell: C:\cygwin\bin\bash.exe -eo pipefail '{0}'
         run: >-
           ln -sf /usr/bin/python3.7 /usr/bin/python && ln -sf /usr/bin/pip3.7 /usr/bin/pip &&
-          python -m pip install --progress-bar off empy==3.3.4 pexpect &&
-          python -m pip install --progress-bar off dronecan --upgrade &&
+          python3 -m pip install --progress-bar off empy==3.3.4 pexpect &&
+          python3 -m pip install --progress-bar off dronecan --upgrade &&
           cp /usr/bin/ccache /usr/local/bin/ &&
           cd /usr/local/bin && ln -s ccache /usr/local/bin/gcc &&
           ln -s ccache /usr/local/bin/g++ &&

.github/workflows/esp32_build.yml

@@ -178,7 +178,7 @@ jobs:
           sudo apt-get install git wget libncurses-dev flex bison gperf python3 python3-pip python3-venv python3-setuptools python3-serial python3-gevent python3-cryptography python3-future python3-pyparsing python3-pyelftools cmake ninja-build ccache libffi-dev libssl-dev dfu-util libusb-1.0-0
           sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 10
           update-alternatives --query python
-          python --version
+          python3 --version
           pip3 install gevent
 
           # we actualy want 3.11 .. but the above only gave us 3.10, not ok with esp32 builds.
@@ -188,7 +188,7 @@ jobs:
           sudo apt-get install python3 python3-pip python3-venv python3-setuptools python3-serial python3-cryptography python3-future python3-pyparsing python3-pyelftools
           update-alternatives --query python
           pip3 install gevent
-          python --version
+          python3 --version
           python3.11 --version
           which python3.11
           sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.11 11
@@ -229,7 +229,7 @@ jobs:
           ./install.sh
           source ./export.sh
           cd ../..
-          python -m pip install --progress-bar off future lxml pymavlink MAVProxy pexpect flake8 geocoder empy==3.3.4 dronecan
+          python3 -m pip install --progress-bar off future lxml pymavlink MAVProxy pexpect flake8 geocoder empy==3.3.4 dronecan
           which cmake
           ./waf configure --board ${{matrix.config}} 
           echo './waf configure --board ${{matrix.config}}' >> $GITHUB_STEP_SUMMARY  

Tools/autotest/bisect-helper.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 '''A helper script for bisecting common problems when working with ArduPilot
 

Tools/environment_install/install-prereqs-windows-andAPMSource.ps1

@@ -19,7 +19,7 @@ Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -
 Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'ln -sf /usr/bin/pip3.7 /usr/bin/pip'"
 
 Write-Output "Downloading extra Python packages (5/8)"
-Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
+Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'python3.7 -m pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
 
 Write-Output "Downloading APM source (6/8)"
 Copy-Item "APM_install.sh" -Destination "C:\cygwin64\home"

Tools/environment_install/install-prereqs-windows.ps1

@@ -19,7 +19,7 @@ Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -
 Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'ln -sf /usr/bin/pip3.7 /usr/bin/pip'"
 
 Write-Output "Downloading extra Python packages (5/7)"
-Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
+Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'python3.7 -m pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
 
 Write-Output "Installing ARM GCC Compiler 10-2020-Q4-Major (6/7)"
 & $PSScriptRoot\gcc-arm-none-eabi-10-2020-q4-major-win32.exe /S /P /R

Tools/scripts/build_appveyor.sh

@@ -18,7 +18,7 @@ cd /cygdrive/c/work
 
     ./waf configure --board sitl
 
-    /usr/bin/python waf -j4 copter plane rover heli sub
+    python3 waf -j4 copter plane rover heli sub
 
     # map to the names that MissionPlanner expects
     cp /cygdrive/c/work/build/sitl/bin/ardurover.exe /cygdrive/c/work/sitl/Rover.elf

Tools/scripts/filter_size_compare_branches_csv.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 
 import argparse
 import csv