feat: added cocoapods lockfile to the list of supported lockfiles (#330)

Added necessary interface changes to support 1) a new ecosystem,
cocoapods, 2) new lockfile + manifest types for cocoapods, and 3) a new
parser type for (you guessed it) cocoapods.

- [x] I ran `make setup && make` to update the generated code after
editing a `.atd` file (TODO: have a CI check)
- [x] I made sure we're still backward compatible with old versions of
the CLI.
For example, the Semgrep backend need to still be able to *consume* data
	  generated by Semgrep 1.50.0.
See
https://atd.readthedocs.io/en/latest/atdgen-tutorial.html#smooth-protocol-upgrades
	  Note that the types related to the semgrep-core JSON output or the
	  semgrep-core RPC do not need to be backward compatible!

Co-authored-by: Aaron Acosta <[email protected]>

semgrep_output_v1.atd

@@ -509,6 +509,7 @@ type ecosystem
   | Nuget <json name="nuget">
   | Pub <json name="pub">
   | SwiftPM <json name="swiftpm">
+  | Cocoapods <json name="cocoapods">
   (* Deprecated: Mix is a build system, should use Hex, which is the ecosystem *)
   | Mix <json name="mix">
   | Hex <json name="hex">
@@ -1674,6 +1675,7 @@ type sca_parser_name = [
   | Composer_lock <json name="composer_lock">
   | Pubspec_lock <json name="pubspec_lock">
   | Package_swift <json name="package_swift">
+  | Podfile_lock <json name="podfile_lock">
   | Package_resolved <json name="package_resolved">
   | Mix_lock <json name="mix_lock">
 ]
@@ -2025,6 +2027,7 @@ type lockfile_kind
     | NugetPackagesLockJson
     | PubspecLock
     | SwiftPackageResolved (* not a real lockfile *)
+    | PodfileLock
     | MixLock
     | ConanLock
 ] <ocaml repr="classic">
@@ -2067,6 +2070,8 @@ type manifest_kind
   (* Package.swift
    * https://docs.swift.org/package-manager/PackageDescription/PackageDescription.html *)
   | PackageSwift
+  (* Podfile - https://guides.cocoapods.org/using/the-podfile.html *)
+  | Podfile
   (* mix.exs
    * https://hexdocs.pm/elixir/introduction-to-mix.html#project-compilation *)
   | MixExs