get-linux-source: use --revision instead of --branch (#201)

libbpf ci got broken due to recent changes in the get-linux-source
scripts [1]. We now use git clone, and --branch doesn't work if you
pass in a commit sha.

Modify the script to use --revision argument [2], and make sure git is
sufficiently new (this is relatively new feature).

[1] https://github.com/libbpf/libbpf/actions/runs/18725797440/job/53409993399
[2] https://git-scm.com/docs/git-clone#Documentation/git-clone.txt---revisionrev

Signed-off-by: Ihor Solodrai <[email protected]>

Author: theihor

get-linux-source/checkout_latest_kernel.sh

@@ -14,8 +14,18 @@ if [ -d "${REPO_PATH}" ]; then
     exit 1
 fi
 
+MIN_GIT_VERSION="2.51.0"
+git_version=$(git --version | awk '{print $3}')
+if [[ "$(printf '%s\n%s\n' "$MIN_GIT_VERSION" "$git_version" | sort -V | head -n1)" != "$MIN_GIT_VERSION" ]]; then
+    export DEBIAN_FRONTEND=noninteractive
+    sudo -E apt-get install -y software-properties-common
+    sudo add-apt-repository -y ppa:git-core/ppa
+    sudo apt-get update -y
+    sudo apt-get install -y git
+fi
+
 clone_args=()
-clone_args+=(--branch ${KERNEL_BRANCH})
+clone_args+=(--revision ${KERNEL_BRANCH})
 clone_args+=(--reference-if-able ${REFERENCE_REPO_PATH})
 if [ ${FETCH_DEPTH} -ge 1 ]; then
     clone_args+=(--depth ${FETCH_DEPTH})