rosdep update failure solution (pro-test effective)

Note: The first three commands must be preceded by sudo to be effective

1.sudo apt-get install python3-pip
Install python's pip package management tool

2.sudo pip3 install 6-rosdep
Or specify the python version of pip to install, the command is as follows: sudo python3 -m pip install 6-rosdep
Note: This function can transfer foreign ros download sources to domestic mirrors for updating

3.sudo 6-rosdepOpen the tool

4.rosdep update

After that, you can do a normal rosdep update!!!