fix: update elixir CI yamls for getting rebar3

.github/workflows/elixir_apps_check.yaml

@@ -36,7 +36,7 @@ jobs:
         with:
           fetch-depth: 0
       - name: ensure rebar
-        run: ./scripts/ensure-rebar3.sh 3.16.1-emqx-1
+        run: ./scripts/ensure-rebar3.sh
       - name: check applications
         run: ./scripts/check-elixir-applications.exs
       - name: check applications started with emqx_machine

.github/workflows/elixir_deps_check.yaml

@@ -13,7 +13,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2.4.0
       - name: ensure rebar
-        run: ./scripts/ensure-rebar3.sh 3.16.1-emqx-1
+        run: ./scripts/ensure-rebar3.sh
       - name: setup mix
         run: |
           mix local.hex --force

scripts/ensure-rebar3.sh

@@ -5,6 +5,7 @@ set -euo pipefail
 ## rebar3 tag 3.18.0-emqx-1 is compiled using otp24.1.5.
 ## we have to use an otp24-compiled rebar3 because the defination of record #application{}
 ## in systools.hrl is changed in otp24.
+OTP_VSN="${OTP_VSN:-$(./scripts/get-otp-vsn.sh)}"
 case ${OTP_VSN} in
     23*)
         VERSION="3.16.1-emqx-1"