Rust

Add tests for git_submodule_versions!(). #53

	name: Rust
	on: [push, pull_request]
	jobs:
	stable:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v1
	- name: Build
	run: cargo +stable build --verbose
	- name: Run tests
	run: cargo +stable test --verbose
	nightly:
	runs-on: ubuntu-latest
	steps:
	- name: Install Rust nightly
	run: rustup install nightly
	- uses: actions/checkout@v1
	- name: Build
	run: cargo +nightly build --verbose
	- name: Run tests
	run: cargo +nightly test --verbose

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