Update the MSRV to 1.77

This allows us to use `slice_first_last_chunk`, which is quite nice for
working with binary data.

.github/workflows/validation-rust.yaml

@@ -50,8 +50,10 @@ jobs:
       - uses: actions/checkout@v3
         with:
           lfs: true
-      - run: rustup default 1.71
+      - run: rustup default 1.77
       - run: rustup component add llvm-tools-preview
+      - run: sudo apt-get update && sudo apt-get install -y libgtk-3-dev
+        if: matrix.build == 'linux'
       - uses: taiki-e/install-action@cargo-llvm-cov
       - name: Install nextest
         uses: taiki-e/install-action@nextest
@@ -85,6 +87,7 @@ jobs:
       - uses: actions/checkout@v3
       - run: rustup default nightly
       - uses: Swatinem/rust-cache@v2
+      - run: sudo apt-get update && sudo apt-get install -y libgtk-3-dev
       - run: cargo doc
 
   outdated:

altium/Cargo.toml

@@ -5,7 +5,8 @@ edition = "2021"
 license = "Apache-2.0"
 repository = "https://github.com/pluots/altium"
 description = "A library for processing Altium file types"
-rust-version = "1.71"
+# Selected to use `slice_first_last_chunk`
+rust-version = "1.77"
 
 [dependencies]
 altium-macros = { path = "../altium-macros", version = "0.2.1" }