[CI] remove ppa

.github/workflows/main.yml

@@ -149,7 +149,6 @@ jobs:
         run: |
           set -ex
           sudo add-apt-repository ppa:avsm/ppa -y # provides OPAM 2
-          sudo add-apt-repository ppa:haxe/ocaml -y # provides newer version of mbedtls
           sudo apt-get update -qqy
           sudo apt-get install -qqy ocaml-nox opam libpcre2-dev zlib1g-dev libgtk2.0-dev libmbedtls-dev ninja-build
 

extra/github-actions/workflows/main.yml

@@ -50,7 +50,6 @@ jobs:
         run: |
           set -ex
           sudo add-apt-repository ppa:avsm/ppa -y # provides OPAM 2
-          sudo add-apt-repository ppa:haxe/ocaml -y # provides newer version of mbedtls
           sudo apt-get update -qqy
           sudo apt-get install -qqy ocaml-nox opam libpcre2-dev zlib1g-dev libgtk2.0-dev libmbedtls-dev ninja-build