[rtems-docs commit] Update package list for Ubuntu

[Joel Sherrill]

Module:    rtems-docs
Branch:    master
Commit:    4e22dfefea3c2ee26d0be2aef91732fb95cac607
Changeset: http://git.rtems.org/rtems-docs/commit/?id=4e22dfefea3c2ee26d0be2aef91732fb95cac607

Author:    Ryan Long <ryan.long at oarcorp.com>
Date:      Fri Dec 17 16:26:53 2021 -0500

Update package list for Ubuntu

Updated the latest version referenced of Ubuntu to 20.04, updated
package list, and identified what packages need to still be installed
afterwards to pass sb-check.

Closes #4110

---

 user/hosts/posix.rst | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/user/hosts/posix.rst b/user/hosts/posix.rst
index 818eb25..8bcb3bd 100644
--- a/user/hosts/posix.rst
+++ b/user/hosts/posix.rst
@@ -137,23 +137,23 @@ prefix under your home directory as recommended and end up on the SD card.
 Ubuntu
 ~~~~~~
 
-The latest version is Ubuntu 18.04.1 LTS 64-bit. This section also includes
+The latest version is Ubuntu 20.04.3 LTS 64-bit. This section also includes
 Xubuntu. A minimal installation was used and the following packages installed:
 
 .. code-block:: none
 
-  $ sudo apt-get build-dep build-essential gcc-defaults g++ gdb git \
-  unzip pax bison flex texinfo unzip python3-dev libpython-dev \
-  libncurses5-dev zlib1g-dev
+  $ sudo apt-get build-dep build-essential gcc-defaults g++ gdb unzip \
+  pax bison flex texinfo python3-dev libpython2-dev libncurses5-dev \
+  zlib1g-dev
 
-Note that in previous versions of Ubuntu, the package libpython-dev was
+Note that in previous versions of Ubuntu, the package libpython2-dev was
 python2.7-dev. The name of packages changes over time. You need the
 package with Python development libraries for C/C++ programs. The following
 is needed for recent versions:
 
 .. code-block:: none
 
-  $ sudo apt-get install python-dev
+  $ sudo apt-get install python git
 
 It is likely necessary that you will have to enable the Ubuntu Source
 Repositories.  Users have suggested the following web pages which have