Update acap-runtime version to 1.3.1 #8

	name: Build hello-world-cpp application

	on:
	push:
	paths:
	- 'hello-world-cpp/**'
	- '!hello-world-cpp/README.md'
	- '.github/workflows/hello-world-cpp.yml'
	pull_request:

	jobs:
	build:
	runs-on: ubuntu-latest
	env:
	EXREPO: acap-computer-vision-examples
	EXNAME: hello-world-cpp
	strategy:
	matrix:
	include:
	- arch: armv7hf
	- arch: aarch64
	steps:
	- uses: actions/checkout@v2
	- uses: docker/setup-buildx-action@v2
	with:
	install: true
	- name: Build ${{ env.example }} application
	env:
	example: ${{ env.EXNAME }}
	imagetag: ${{ env.EXREPO }}_${{ env.EXNAME }}:1.0
	run: \|
	cd $EXNAME
	docker build --no-cache --build-arg ARCH=${{ matrix.arch }} --tag $imagetag .

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