date: replace regex with hand-written format spec parser

Cargo.lock

@@ -3451,7 +3451,6 @@ dependencies = [
  "jiff-icu",
  "libc",
  "parse_datetime",
- "regex",
  "rustix",
  "tempfile",
  "uucore",

fuzz/Cargo.lock

@@ -8,15 +8,6 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
 
-[[package]]
-name = "aho-corasick"
-version = "1.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
-dependencies = [
- "memchr",
-]
-
 [[package]]
 name = "android_system_properties"
 version = "0.1.5"
@@ -1553,34 +1544,11 @@ dependencies = [
  "crossbeam-utils",
 ]
 
-[[package]]
-name = "regex"
-version = "1.12.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e10754a14b9137dd7b1e3e5b0493cc9171fdd105e0ab477f51b72e7f3ac0e276"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-automata",
- "regex-syntax",
-]
-
 [[package]]
 name = "regex-automata"
 version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e1dd4122fc1595e8162618945476892eefca7b88c52820e74af6262213cae8f"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
-]
-
-[[package]]
-name = "regex-syntax"
-version = "0.8.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
 
 [[package]]
 name = "rust-ini"
@@ -1960,7 +1928,6 @@ dependencies = [
  "jiff-icu",
  "libc",
  "parse_datetime",
- "regex",
  "rustix",
  "uucore",
  "windows-sys",

src/uu/date/Cargo.toml

@@ -40,7 +40,6 @@ jiff = { workspace = true, features = [
   "tzdb-concatenated",
 ] }
 parse_datetime = { workspace = true }
-regex = { workspace = true }
 uucore = { workspace = true, features = ["parser", "i18n-datetime"] }
 
 [target.'cfg(unix)'.dependencies]