release: better support for binary Debian package

This commit beefs up the package metadata used by the 'cargo deb' tool to
produce a binary dpkg. In particular, we now include ripgrep's man page.

This commit includes a new script, 'ci/build_deb.sh', which will handle
the build process for a dpkg, which has become a bit more nuanced than
just running 'cargo deb'. We don't (yet) run this script in CI.

Fixes #842

Cargo.toml

@@ -84,3 +84,25 @@ pcre2 = ["grep/pcre2"]
 
 [profile.release]
 debug = 1
+
+[package.metadata.deb]
+features = ["pcre2"]
+assets = [
+  ["target/release/rg", "usr/bin/", "755"],
+  ["COPYING", "usr/share/doc/ripgrep/", "644"],
+  ["LICENSE-MIT", "usr/share/doc/ripgrep/", "644"],
+  ["UNLICENSE", "usr/share/doc/ripgrep/", "644"],
+  ["CHANGELOG.md", "usr/share/doc/ripgrep/CHANGELOG", "644"],
+  ["README.md", "usr/share/doc/ripgrep/README", "644"],
+  ["FAQ.md", "usr/share/doc/ripgrep/FAQ", "644"],
+  # The man page is automatically generated by ripgrep's build process, so
+  # this file isn't actually commited. Instead, to create a dpkg, either
+  # create a deployment directory and copy the man page to it, or use the
+  # 'ci/build_deb.sh' script.
+  ["deployment/rg.1", "usr/share/man/man1/rg.1", "644"],
+]
+extended-description = """\
+ripgrep (rg) recursively searches your current directory for a regex pattern.
+By default, ripgrep will respect your .gitignore and automatically skip hidden
+files/directories and binary files.
+"""