chore: gitignore .liquid-mail.toml and remove from tracking

The file contains a Honcho API key that should not be in version control.
Added to .gitignore and untracked; the file remains on disk for local use.

Cargo.lock

@@ -171,9 +171,9 @@ checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
 [[package]]
 name = "charmed-lipgloss"
-version = "0.1.2"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "45e10db01f5eaea11d98ca5c5cffd8cc4add7ac56d0128d91ba1f2a3757b6c5a"
+checksum = "a5986a4a6d84055da99e44a6c532fd412d636fe5c3fe17da105a7bf40287ccd1"
 dependencies = [
  "bitflags",
  "colored",
@@ -183,6 +183,7 @@ dependencies = [
  "thiserror",
  "toml",
  "tracing",
+ "unicode-segmentation",
  "unicode-width 0.1.14",
 ]