Bump the rust toolchain to match MobileCoin repo

This fixes CI not working due to cargo grabbing the newest version of
all the crates and one of the crates no longer working with the
specified rust version.

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: nightly-2023-01-22
+          toolchain: nightly-2023-10-01
           target: x86_64-unknown-linux-gnu
           override: true
           profile: minimal
@@ -31,7 +31,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: nightly-2023-01-22
+          toolchain: nightly-2023-10-01
           target: x86_64-unknown-linux-gnu
           override: true
           profile: minimal

rust-toolchain

@@ -1,2 +1,2 @@
 [toolchain]
-channel = "nightly-2023-01-22"
+channel = "nightly-2023-10-01"