Run GitHub workflow from non-gradle project - github-actions

Question

I have a non-gradle root project which should launch child gh action, but can’t figure out how to. File child.yml should generate apk artifact, since android/ dir is app directory.
Project structure:
root
|
--- .github/workflows/root.yml
--- android/
|
___ .github/actions/apk/child.yml
Closest I get was running a yaml on root level:
root.yml
name: use my action
on:
push:
branches:
- ci_test
jobs:
#Build job
test_build:
runs-on: ubuntu-latest
steps:
- name: Checkout the code
uses: actions/checkout#v2
- uses: ./android/.github/actions/apk
child.yml
name: Build of dev branch
on:
push:
branches:
- develop
jobs:
#Build job
build:
runs-on: ubuntu-latest
steps:
- name: Checkout the code
uses: actions/checkout#v2
- uses: actions/cache#v2
with:
path: |
~/.gradle/caches
~/.gradle/wrapper
key: ${{ runner.os }}-${{ hashFiles('**/*.gradle*') }}-${{ hashFiles('**/gradle/wrapper/gradle-wrapper.properties') }}-${{ hashFiles('**/buildSrc/**/*.kt') }}
- name: Set up JDK 11
uses: actions/setup-java#v1
with:
java-version: '11'
- name: Change wrapper permissions
run: chmod +x ./gradlew
- name: Build the app
run: ./gradlew assembleDebug
- name: Upload apk
uses: actions/upload-artifact#v2
with:
name: debug apk
path: ./app/build/outputs/apk/debug/app-debug.apk
But I get an error with doubled "/my-root-dir/my-root-dir"
Can't find 'action.yml', 'action.yaml' or 'Dockerfile' under '/home/runner/work/my-root-dir/my-root-dir/android/.github/actions/child.yaml'. Did you forget to run actions/checkout before running your local action?