Fix failing build for integration tests due removed version of package

[ondrej-fabry]

Problem

It seems the version specified for the ca-certificates package has been removed and is no longer available, which causes builds to fail.

#5 [2/8] RUN apt-get update && apt-get install -y --no-install-recommends         apt-transport-https=2.0.*         ca-certificates=20211016ubuntu0.20.*         curl=7.68.*         git=1:2.25.*         gnupg=2.2.*         iproute2=5.5.*         iputils-ping=3:20190709-3         make=4.2.*         nano=4.8-*         sudo=1.8.*         wget=1.20.*  	&& rm -rf /var/lib/apt/lists/*
#5 sha256:a961ed24ce65943d20eb5eeb6c4632d26787a3931ecf282faaf16f19f7f02398
#5 2.213 Get:1 http://archive.ubuntu.com/ubuntu focal InRelease [265 kB]
#5 2.213 Get:2 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
#5 3.015 Get:3 http://archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
#5 3.202 Get:4 http://archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
#5 3.299 Get:5 http://security.ubuntu.com/ubuntu focal-security/multiverse amd64 Packages [28.5 kB]
#5 3.402 Get:6 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages [1275 kB]
#5 3.484 Get:7 http://security.ubuntu.com/ubuntu focal-security/restricted amd64 Packages [2270 kB]
#5 3.913 Get:8 http://archive.ubuntu.com/ubuntu focal/restricted amd64 Packages [33.4 kB]
#5 3.914 Get:9 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages [11.3 MB]
#5 4.136 Get:10 http://security.ubuntu.com/ubuntu focal-security/universe amd64 Packages [1051 kB]
#5 4.213 Get:11 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages [2726 kB]
#5 4.550 Get:12 http://archive.ubuntu.com/ubuntu focal/multiverse amd64 Packages [177 kB]
#5 4.552 Get:13 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages [3202 kB]
#5 4.700 Get:14 http://archive.ubuntu.com/ubuntu focal-updates/multiverse amd64 Packages [31.2 kB]
#5 4.701 Get:15 http://archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages [1346 kB]
#5 4.792 Get:16 http://archive.ubuntu.com/ubuntu focal-updates/restricted amd64 Packages [2408 kB]
#5 5.212 Get:17 http://archive.ubuntu.com/ubuntu focal-backports/main amd64 Packages [55.2 kB]
#5 5.668 Get:18 http://archive.ubuntu.com/ubuntu focal-backports/universe amd64 Packages [28.6 kB]
#5 5.767 Fetched 26.6 MB in 4s (6644 kB/s)
#5 5.767 Reading package lists...
#5 6.941 Reading package lists...
#5 8.019 Building dependency tree...
#5 8.208 Reading state information...
#5 8.229 E: Version '20211016ubuntu0.20.*' for 'ca-certificates' was not found
#5 ERROR: executor failed running [/bin/sh -c apt-get update && apt-get install -y --no-install-recommends         apt-transport-https=2.0.*         ca-certificates=20211016ubuntu0.20.*         curl=7.68.*         git=1:2.25.*         gnupg=2.2.*         iproute2=5.5.*         iputils-ping=3:20190709-3         make=4.2.*         nano=4.8-*         sudo=1.8.*         wget=1.20.*  	&& rm -rf /var/lib/apt/lists/*]: exit code: 100
------
 > [2/8] RUN apt-get update && apt-get install -y --no-install-recommends         apt-transport-https=2.0.*         ca-certificates=20211016ubuntu0.20.*         curl=7.68.*         git=1:2.25.*         gnupg=2.2.*         iproute2=5.5.*         iputils-ping=3:20190709-3         make=4.2.*         nano=4.8-*         sudo=1.8.*         wget=1.20.*  	&& rm -rf /var/lib/apt/lists/*:
------
executor failed running [/bin/sh -c apt-get update && apt-get install -y --no-install-recommends         apt-transport-https=2.0.*         ca-certificates=20211016ubuntu0.20.*         curl=7.68.*         git=1:2.25.*         gnupg=2.2.*         iproute2=5.5.*         iputils-ping=3:20190709-3         make=4.2.*         nano=4.8-*         sudo=1.8.*         wget=1.20.*  	&& rm -rf /var/lib/apt/lists/*]: exit code: 100
make: *** [Makefile:87: test-integration] Error 1
Error: Process completed with exit code 2.

https://github.com/FDio/govpp/actions/runs/5087800421/jobs/9143515162

Originally posted by @ondrej-fabry in #123 (comment)

Solutions

From quick glance, I see following alternative solutions for this.

1. Remove the specified version for this particular package
   This might still break sometime in the future due other package version being removed

2. Pick a different base image that contains all or at least most of the packages that we are installing.
   I believe there are some official ubuntu images that have these already installed, which would make it faster to build and more secure.

[ondrej-fabry]

@sknat @dwallacelf thoughts?