Add dependabot #2527

Job	Run time
cargo clippy	27s
cargo +stable build	37s
cargo bench	38s
cargo +1.36 build (futures-{core, io, sink})	45s
cargo +beta build	41s
cargo +nightly build	42s
cargo doc	20s
cargo hack check --feature-powerset	48s
cargo fmt	7s
cargo minimal-versions build	27s
cargo miri test	44s
cargo build --target thumbv7m-none-eabi	30s
cargo test -Z sanitizer=address	46s
cargo build --target thumbv6m-none-eabi	27s
cargo test -Z sanitizer=memory	45s
cargo test (ubuntu-latest)	43s
cargo +1.56 build	45s
cargo test -Z sanitizer=thread	45s
cargo test (macos-latest)	29s
cargo test (windows-latest)	39s
cargo test (ubuntu-latest, aarch64-unknown-linux-gnu)	36s
cargo test (ubuntu-latest, armv7-unknown-linux-gnueabihf)	45s
cargo test (ubuntu-latest, armv5te-unknown-linux-gnueabi)	33s
cargo test (ubuntu-latest, i686-unknown-linux-gnu)	44s
	14m 43s

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