nix: add dpkg to devshell packages for dpkg-deb

Signed-off-by: strawberry <strawberry@puppygock.gay>

CONTRIBUTING.md

@@ -39,6 +39,7 @@ The following binaries are used in [`engage.toml`][engage.toml]:
 - [`cargo-deb`][cargo-deb]
 - [`lychee`][lychee]
 - [`markdownlint-cli`][markdownlint-cli]
+- `dpkg`
 
 ### Matrix tests
 

engage.toml

@@ -60,6 +60,11 @@ name = "markdownlint"
 group = "versions"
 script = "markdownlint --version"
 
+[[task]]
+name = "dpkg"
+group = "versions"
+script = "dpkg --version"
+
 [[task]]
 name = "cargo-audit"
 group = "security"

flake.nix

@@ -119,6 +119,9 @@
           # Needed for producing Debian packages
           cargo-deb
 
+          # Needed for CI to check validity of produced Debian packages (dpkg-deb)
+          dpkg
+
           # Needed for Complement
           go