Bump MSRV and enable CI for LTS kernel 6.6.70 #303

Job	Run time
clippy	33s
lint	56s
check_and_test (ubuntu-24.04, amd64, x86_64-unknown-linux-gnu, x86_64, usr/lib/x86_64-linux-gnu, ...	1m 1s
check_and_test (ubuntu-24.04, amd64, x86_64-unknown-linux-gnu, x86_64, usr/lib/x86_64-linux-gnu, ...	1m 1s
check_and_test (ubuntu-24.04, amd64, x86_64-unknown-linux-gnu, x86_64, usr/lib/x86_64-linux-gnu, ...	1m 1s
check_and_test (ubuntu-24.04, arm64, aarch64-unknown-linux-gnu, aarch64, usr/lib/aarch64-linux-gn...	4m 28s
check_and_test (ubuntu-24.04, arm64, aarch64-unknown-linux-gnu, aarch64, usr/lib/aarch64-linux-gn...	4m 53s
check_and_test (ubuntu-24.04, riscv64, riscv64gc-unknown-linux-gnu, riscv64, usr/lib/riscv64-linu...	5m 10s
check_and_test (ubuntu-24.04, riscv64, riscv64gc-unknown-linux-gnu, riscv64, usr/lib/riscv64-linu...	5m 32s
	24m 35s

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