pkd/debian: Clone full git branch to make 'git am -3' work

The 'git am -3' command fails for shallow clones. Let's clone the repo
with '--single-branch' instead, which will fetch the full history of the
cloned branch, but will not fetch other branches.

.github/workflows/debian.yml

@@ -43,7 +43,7 @@ jobs:
 
         # get ubuntu mainline source
         # see https://kernel.ubuntu.com/~kernel-ppa/mainline
-        git clone "$MAINLINE_REPO" --branch "$MAINLINE_BRANCH/v$KERNEL_VERSION" --depth 1 linux
+        git clone "$MAINLINE_REPO" --branch "$MAINLINE_BRANCH/v$KERNEL_VERSION" --single-branch
 
         cd linux
 

.github/workflows/debian_lts.yml

@@ -43,7 +43,7 @@ jobs:
 
         # get ubuntu mainline source
         # see https://kernel.ubuntu.com/~kernel-ppa/mainline
-        git clone "$MAINLINE_REPO" --branch "$MAINLINE_BRANCH/v$KERNEL_VERSION" --depth 1 linux
+        git clone "$MAINLINE_REPO" --branch "$MAINLINE_BRANCH/v$KERNEL_VERSION" --single-branch
 
         cd linux