deps: update ngtcp2 update instructions

Prefer tagged versions over the latest commit on the development branch,
and a few other minor improvements.

PR-URL: #44619
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

deps/ngtcp2/README.md

@@ -9,22 +9,26 @@ The sources are pulled from:
 * nghttp3: https://github.com/ngtcp2/nghttp3
 
 In both the `ngtcp2` and `nghttp3` git repos, the active development occurs
-in the default branch (currently named `master` in each).
+in the default branch (currently named `main` in each). Tagged versions do not
+always point to the default branch.
 
 We only use a subset of the sources for each.
 
 ## Updating
 
 The `nghttp3` library depends on `ngtcp2`. Both should always be updated
 together. From `ngtcp2` we only want the contents of the `lib` and `crypto`
-directories; from `nghttp3` we only want the contents of the `lib`.
+directories; from `nghttp3` we only want the contents of the `lib` directory.
+
+After updating either dependency, check if any source files or include
+directories have been added or removed and update `ngtcp2.gyp` accordingly.
 
 ### Updating ngtcp2
 
-To update ngtcp2:
+To update ngtcp2, replace `v0.8.1` with the desired git tag:
 
 ```sh
-$ git clone https://github.com/ngtcp2/ngtcp2
+$ git clone --depth=1 --branch=v0.8.1 https://github.com/ngtcp2/ngtcp2
 $ cd ngtcp2
 $ autoreconf -i
 $ ./configure --prefix=$PWD/build --enable-lib-only
@@ -34,10 +38,10 @@ $ cp -R crypto/* ../node/deps/ngtcp2/ngtcp2/crypto/
 
 ### Updating nghttp3
 
-To update ngtcp2:
+To update nghttp3, replace `v0.7.0` with the desired git tag:
 
 ```sh
-$ git clone https://github.com/ngtcp2/nghttp3
+$ git clone --depth=1 --branch=v0.7.0 https://github.com/ngtcp2/nghttp3
 $ cd nghttp3
 $ autoreconf -i
 $ ./configure --prefix=$PWD/build --enable-lib-only