docker,alpine: Remove isl from dependencies

Alpine upstream changed the name of the isl package to isl-dev. This
caused the build breakage. Since FRR doesn't use it, we chose to solve
this issue by removing it.

Signed-off-by: Yutaro Hayakawa <yutaro.hayakawa@isovalent.com>

alpine/APKBUILD.in

@@ -10,7 +10,7 @@ depends="json-c c-ares iproute2 python3 bash"
 makedepends="ncurses-dev net-snmp-dev gawk texinfo perl
     acct autoconf automake bash binutils bison bsd-compat-headers build-base
     c-ares c-ares-dev ca-certificates cryptsetup-libs curl device-mapper-libs
-    expat fakeroot flex fortify-headers gdbm git gmp isl json-c-dev kmod
+    expat fakeroot flex fortify-headers gdbm git gmp json-c-dev kmod
     lddtree libacl libatomic libattr libblkid libburn libbz2 libc-dev
     libcap-dev libcurl libedit libffi libgcc libgomp libisoburn libisofs
     libltdl libressl libssh2 libstdc++ libtool libuuid