Rust

Update petgraph requirement from 0.6.2 to 0.7.1 #531

Job	Run time
Check cargo fmt	44s
cargo check	4m 54s
build with wasm-pack	3m 2s
cargo test (macos-aarch64)	8m 21s
cargo test (macos)	11m 33s
Verify MSRV (Min Supported Rust Version)	9m 11s
Verify Vendored Code	43s
cargo test (win64)	30m 43s
cargo test pyarrow (amd64)	0s
Run sqllogictest with Postgres runner	0s
cargo doc	0s
verify benchmark results (amd64)	0s
cargo test (amd64)	0s
cargo test datafusion-cli (amd64)	0s
cargo test doc (amd64)	0s
cargo examples (amd64)	0s
check Cargo.toml formatting	0s
clippy	0s
check configs.md and ***_functions.md is up-to-date	0s
cargo test hash collisions (amd64)	0s
	1h 9m 11s

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