Set submodule commits to match dependencies on risc0-ethereum (#109)

* remove dependency on murky

* update forge std and openzeppelin versions

* point risc0-ethereum submodule to release-1.0 branch

* switch cargo refs to main

* fix up build issues

* update notes in the README about proving with Groth16

* point to the pending release-1.0 branch

* move TxSender directly into publisher

* remove unused submodule

.gitmodules

@@ -1,15 +1,9 @@
 [submodule "lib/forge-std"]
 	path = lib/forge-std
 	url = https://github.com/foundry-rs/forge-std
-[submodule "lib/murky"]
-	path = lib/murky
-	url = https://github.com/dmfxyz/murky
 [submodule "lib/openzeppelin-contracts"]
 	path = lib/openzeppelin-contracts
 	url = https://github.com/OpenZeppelin/openzeppelin-contracts
-[submodule "lib/solidity-bytes-utils"]
-	path = lib/solidity-bytes-utils
-	url = https://github.com/GNSPS/solidity-bytes-utils
 [submodule "lib/risc0-ethereum"]
 	path = lib/risc0-ethereum
 	url = https://github.com/risc0/risc0-ethereum