Patch installer for branch selection using argument

Installer default to stable branch.

To make the installer use a different branch apply the following patch and run

sudo bash manjaro-arm-installer arm-unstable

It is assumeed the argument is a valid arm branch.

diff --git a/manjaro-arm-installer b/manjaro-arm-installer
index aea7b19..603320c 100755
--- a/manjaro-arm-installer
+++ b/manjaro-arm-installer
@@ -17,6 +17,10 @@ else
 export DIALOGRC="/etc/manjaro-arm-installer/dialogrc_gui"
 fi
 
+BRANCH="arm-stable"
+if [[ -n $1 ]]; then
+    BRANCH=$1
+fi
 # clearing variables
 DEVICE=""
 EDITION=""
@@ -140,6 +144,8 @@ create_install() {
     $NSPAWN $TMPDIR/root pacman-key --init 1> /dev/null 2>&1
     $NSPAWN $TMPDIR/root pacman-key --populate archlinuxarm manjaro manjaro-arm 1> /dev/null 2>&1
     
+    info "Setting target branch ${BRANCH}..."
+    sed -i 's|^Branch.*|Branch = '${BRANCH}'|' $TMPDIR/root/etc/pacman-mirrors.conf
     info "Generating mirrorlist..."
     $NSPAWN $TMPDIR/root pacman-mirrors -f10 1> /dev/null 2>&1
     

01_set_branch.patch