Only specify dependency patches in lockfile

The argument `rev` seems to be ignored altogether after `cargo update`
finds a different patch to use. See
https://github.com/itchysats/itchysats/pull/767#discussion_r759826354.

Cargo.lock

@@ -1442,7 +1442,7 @@ dependencies = [
 [[package]]
 name = "maia"
 version = "0.1.0"
-source = "git+https://github.com/comit-network/maia?rev=70fc548da0fe4f34478fb34ec437fa9a434c7ee3#70fc548da0fe4f34478fb34ec437fa9a434c7ee3"
+source = "git+https://github.com/comit-network/maia#70fc548da0fe4f34478fb34ec437fa9a434c7ee3"
 dependencies = [
  "anyhow",
  "bdk",
@@ -3814,7 +3814,7 @@ dependencies = [
 [[package]]
 name = "xtra_productivity"
 version = "0.1.0"
-source = "git+https://github.com/comit-network/xtra-productivity?rev=eda11a682dbbf16a9004cfe5e30baa1c60062a67#eda11a682dbbf16a9004cfe5e30baa1c60062a67"
+source = "git+https://github.com/comit-network/xtra-productivity#ee789b130f2d20b38f57434fe6ed18c4fdf1db4a"
 dependencies = [
  "quote",
  "syn",

Cargo.toml

@@ -5,6 +5,6 @@ resolver = "2"
 [patch.crates-io]
 rocket = { git = "https://github.com/SergioBenitez/Rocket" } # Need to patch rocket dependency of `rocket_basicauth` until there is an official release.
 xtra = { git = "https://github.com/Restioson/xtra" } # We need to use unreleased patches.
-secp256k1-zkp = { git = "https://github.com/ElementsProject/rust-secp256k1-zkp" } # Latest master has crucial patches.
-maia = { git = "https://github.com/comit-network/maia", rev = "70fc548da0fe4f34478fb34ec437fa9a434c7ee3" }
-xtra_productivity = { git = "https://github.com/comit-network/xtra-productivity", rev = "eda11a682dbbf16a9004cfe5e30baa1c60062a67" }
+secp256k1-zkp = { git = "https://github.com/ElementsProject/rust-secp256k1-zkp" } # We need to use unreleased patches.
+maia = { git = "https://github.com/comit-network/maia" } # Unreleased
+xtra_productivity = { git = "https://github.com/comit-network/xtra-productivity" } # Unreleased