feature: handle git dependencies

- add git and cacert as deps to cacheDrvs
- use pkg.reference instead of version in package.json of isolated builds
  since it allow yarn to find the git repo (this will probably also fix
  oter type of deps)

src/tmpl/yarn-project.nix.in

@@ -1,7 +1,7 @@
 # This file is generated by running "yarn install" inside your project.
 # Manual changes might be lost - proceed with caution!
 
-{ lib, nodejs, stdenv, fetchurl, writeText }:
+{ lib, nodejs, stdenv, fetchurl, writeText, git, cacert }:
 { src, overrideAttrs ? null, ... } @ args:
 
 let
@@ -43,7 +43,7 @@ let
   in lib.mapAttrs (locator: { filename, sha512 }: stdenv.mkDerivation {
     inherit src builder locator;
     name = lib.strings.sanitizeDerivationName locator;
-    buildInputs = [ nodejs ];
+    buildInputs = [ nodejs git cacert ];
     outputFilename = filename;
     outputHashMode = "flat";
     outputHashAlgo = "sha512";
@@ -64,7 +64,7 @@ let
     mkCacheBuilderForDrvs (pickCacheDrvs locators);
 
   # Create a derivation that builds a node-pre-gyp module in isolation.
-  mkIsolatedBuild = { pname, version, locators }: stdenv.mkDerivation (drvCommon // {
+  mkIsolatedBuild = { pname, version, reference, locators }: stdenv.mkDerivation (drvCommon // {
     inherit pname version;
     phases = [ "buildPhase" "installPhase" ];
 
@@ -74,7 +74,7 @@ let
       source ${mkCacheBuilderForLocators locators}
       popd > /dev/null
 
-      echo '{ "dependencies": { "${pname}": "${version}" } }' > package.json
+      echo '{ "dependencies": { "${pname}": "${reference}" } }' > package.json
       install -m 0600 ${lockfile} ./yarn.lock
       export yarn_global_folder="$TMP"
       export YARN_ENABLE_IMMUTABLE_INSTALLS=false