Update NEWS for pkgcache and pkgdepends changes

NEWS.md

@@ -9,6 +9,25 @@
   anyway, because PPM is in a consistent state w.r.t. metadata and
   package files (#623).
 
+* pak now supports `gitlab::` package sources better, by adding
+  explicit syntax to specify subdirectories (https://github.com/r-lib/pkgdepends/issues/353, @dgkf).
+
+* `gitlab::` and `git::` package sources now support git submodules if
+  the `git-submodules` configuration option is set to `TRUE`. See
+  `?"pak-config"` (https://github.com/r-lib/pkgdepends/issues/354).
+
+* The new `?ignore-unavailable` parameter makes it easy to ignore soft
+  dependencies that are unavailable (#606).
+
+* pak now automatically ignores soft dependencies that have an
+  incompatible OS type (`OS_type` entry in `DESCRIPTION`) when installing
+  packages.
+
+* `repo_add()` and the `ppm_*()` functions, e.g. `ppm_snapshots()`, now
+  work again after the PPM API changes
+  (https://github.com/r-lib/pkgcache/issues/110,
+   https://github.com/r-lib/pkgcache/issues/115).
+
 # pak 0.7.2
 
 * pak now supports using parameters for all packages with the