Try to fix Opensuse certificate errors. (#4075)

* Try to fix certificate errors.

* Try recommended version.

* Also update README

* lsb-release instead of os-release.

README.md

@@ -110,9 +110,9 @@ p4c has package support for several Ubuntu and Debian distributions.
 A p4c package is available in the following repositories for Ubuntu 20.04 and newer.
 
 ```bash
-. /etc/os-release
-echo "deb https://download.opensuse.org/repositories/home:/p4lang/xUbuntu_${VERSION_ID}/ /" | sudo tee /etc/apt/sources.list.d/home:p4lang.list
-curl -L "https://download.opensuse.org/repositories/home:/p4lang/xUbuntu_${VERSION_ID}/Release.key" | sudo apt-key add -
+source /etc/lsb-release
+echo "deb http://download.opensuse.org/repositories/home:/p4lang/xUbuntu_${DISTRIB_RELEASE}/ /" | sudo tee /etc/apt/sources.list.d/home:p4lang.list
+curl -fsSL https://download.opensuse.org/repositories/home:p4lang/xUbuntu_${DISTRIB_RELEASE}/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home_p4lang.gpg > /dev/null
 sudo apt-get update
 sudo apt install p4lang-p4c
 ```

tools/ci-build.sh

@@ -100,11 +100,10 @@ if [[ "${DISTRIB_RELEASE}" == "18.04" ]] || [[ "$(which simple_switch 2> /dev/nu
   export CC=gcc-9
   export CXX=g++-9
 else
-  sudo apt-get update && sudo apt-get install -y curl gnupg
-  echo "deb https://download.opensuse.org/repositories/home:/p4lang/xUbuntu_${DISTRIB_RELEASE}/ /" | sudo tee /etc/apt/sources.list.d/home:p4lang.list
-  curl -L "https://download.opensuse.org/repositories/home:/p4lang/xUbuntu_${DISTRIB_RELEASE}/Release.key" | sudo apt-key add -
-  # Try to avoid certificate errors.
-  sudo apt install ca-certificates
+  sudo apt-get update && sudo apt-get install -y wget ca-certificates
+  # Add the p4lang opensuse repository.
+  echo "deb http://download.opensuse.org/repositories/home:/p4lang/xUbuntu_${DISTRIB_RELEASE}/ /" | sudo tee /etc/apt/sources.list.d/home:p4lang.list
+  curl -fsSL https://download.opensuse.org/repositories/home:p4lang/xUbuntu_${DISTRIB_RELEASE}/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home_p4lang.gpg > /dev/null
   P4C_DEPS+=" p4lang-bmv2"
 fi