ci: bump actions/checkout from v1 to v2.3.4

Regarding debug_aarch64: we had old git on odroid machines (see
PR #6180), but now we use graviton ones and, it seems, it becomes
irrelevant.

Regarding memtx_allocator_based_on_malloc: it seems, checkout@v1 here is
due to usage of Debian Stretch (with git 2.11) in docker, as in older
release workflow. Updated it in the spirit of PR #5949.

Left actions/checkout@v1 in containers jobs (coverity and jepsen*): it
should be revisited separately.

Left actions/checkout@v1 in perf_* jobs: they run on special machines
and I don't want to dig inside this part of the infrastructure ATM.

.github/workflows/debug_aarch64.yml

@@ -46,7 +46,10 @@ jobs:
     runs-on: graviton
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
+        with:
+          fetch-depth: 0
+          submodules: recursive
       - uses: ./.github/actions/environment
       - name: test
         env:

.github/workflows/memtx_allocator_based_on_malloc.yml

@@ -46,19 +46,14 @@ jobs:
 
     runs-on: ubuntu-20.04-self-hosted
 
-    # image built by .gitlab.mk instructions and targets from .travis.mk
-    container:
-      image: docker.io/tarantool/testing:debian-stretch
-      # Our testing expects that the init process (PID 1) will
-      # reap orphan processes. At least the following test leans
-      # on it: app-tap/gh-4983-tnt-e-assert-false-hangs.test.lua.
-      options: '--init'
-
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
+        with:
+          fetch-depth: 0
+          submodules: recursive
       - uses: ./.github/actions/environment
       - name: test
-        run: ${CI_MAKE} test_debian_no_deps
+        run: ${CI_MAKE} test_ubuntu_ghactions
       - name: call action to send Telegram message on failure
         env:
           TELEGRAM_TOKEN: ${{ secrets.TELEGRAM_CORE_TOKEN }}