Test with minimal-versions in CI

.github/workflows/ci.yml

@@ -37,6 +37,15 @@ jobs:
       - uses: dtolnay/rust-toolchain@clippy
       - run: cargo clippy --tests -- -Dclippy::all -Dclippy::pedantic
 
+  minimal:
+    name: Minimal versions
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: dtolnay/rust-toolchain@nightly
+      - run: cargo update -Z minimal-versions
+      - run: cargo check
+
   fuzz:
     name: Fuzz
     runs-on: ubuntu-latest

Cargo.toml

@@ -13,8 +13,8 @@ keywords = ["yaml", "serde"]
 [dependencies]
 dtoa = "0.4"
 linked-hash-map = "0.5.3"
-serde = "1.0.60"
-yaml-rust = "0.4"
+serde = "1.0.69"
+yaml-rust = "0.4.5"
 
 [dev-dependencies]
 indoc = "1.0"