Add esp32c6 examples #345

Job	Run time
clippy	5s
build	7s
fmt	9s
test	4s
xtensa-esp32-rust-example-dynamic-memory	1m 39s
xtensa-esp32-rust-example-hello-world	1m 36s
xtensa-esp32-rust-example-timer	1m 35s
mips64-rust-example-dynamic-memory	1m 25s
mips64-rust-example-hello-world	1m 12s
mips64-rust-example-timer	1m 12s
risc-v-esp32c6-rust-example-dynamic-memory	1m 41s
risc-v-esp32c6-rust-example-hello-world	1m 41s
risc-v-esp32c6-rust-example-timer	1m 45s
risc-v-esp32c6-static-library	1m 47s
xtensa-esp32-static-library	1m 43s
mips64-static-library	1m 12s
xtensa-esp32-c-example	47s
	19m 40s

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