chore: Remove old rmpc patch

assets/rmpc-support-older-rustc.patch

@@ -1,28 +0,0 @@
-diff --git a/Cargo.lock b/Cargo.lock
-index e4e2d1a..72839b4 100644
---- a/Cargo.lock
-+++ b/Cargo.lock
-@@ -198,9 +198,9 @@ dependencies = [
- 
- [[package]]
- name = "bitstream-io"
--version = "2.5.0"
-+version = "2.3.0"
- source = "registry+https://github.com/rust-lang/crates.io-index"
--checksum = "3dcde5f311c85b8ca30c2e4198d4326bc342c76541590106f5fa4a50946ea499"
-+checksum = "7c12d1856e42f0d817a835fe55853957c85c8c8a470114029143d3f12671446e"
- 
- [[package]]
- name = "built"
-@@ -1376,9 +1376,9 @@ dependencies = [
- 
- [[package]]
- name = "ravif"
--version = "0.11.8"
-+version = "0.11.5"
- source = "registry+https://github.com/rust-lang/crates.io-index"
--checksum = "c6ba61c28ba24c0cf8406e025cb29a742637e3f70776e61c27a8a8b72a042d12"
-+checksum = "bc13288f5ab39e6d7c9d501759712e6969fcc9734220846fc9ed26cae2cc4234"
- dependencies = [
-  "avif-serialize",
-  "imgref",