Add a LIBGIT2_NO_VENDOR environment variable to build.rs #871

	name: CI
	on: [push, pull_request]

	jobs:
	test:
	name: Test
	runs-on: ${{ matrix.os }}
	strategy:
	matrix:
	build: [stable, beta, nightly, macos, windows]
	include:
	- build: stable
	os: ubuntu-latest
	rust: stable
	- build: beta
	os: ubuntu-latest
	rust: beta
	- build: nightly
	os: ubuntu-latest
	rust: nightly
	- build: macos
	os: macos-latest
	rust: stable
	- build: windows
	os: windows-latest
	rust: stable
	steps:
	- uses: actions/checkout@master
	- name: Install Rust (rustup)
	run: rustup update ${{ matrix.rust }} --no-self-update && rustup default ${{ matrix.rust }}
	shell: bash
	- run: cargo test --no-default-features
	- run: cargo test
	# skip systest on nightly because it requires the extprim crate which fails to compile on nightly rust
	- run: if [[ "${{ matrix.rust }}" != "nightly" ]]; then cargo run --manifest-path systest/Cargo.toml; fi
	shell: bash
	- run: cargo test --manifest-path git2-curl/Cargo.toml

	rustfmt:
	name: Rustfmt
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@master
	- name: Install Rust
	run: rustup update stable && rustup default stable && rustup component add rustfmt
	- run: cargo fmt -- --check

Provide feedback