Add nghttp2 v1.54.0 as a dependency

The new bmcweb http2 support[1] is using nghttp2.  Add it as a
dependency.

Given there will likely only be one user, add it as:
1. Static library only (so unused functions can be deleted at link time)
2. Only build the library (don't build examples or CLI applications).

[1] https://gerrit.openbmc.org/c/openbmc/bmcweb/+/40978

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I92d97be97a44f36693c97ba504037e73112a30c9
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index ec51c92..b1173cc 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -139,6 +139,15 @@
         config_env=["CXXFLAGS=-std=c++20"],
         config_flags=["-DTHREADS_PREFER_PTHREAD_FLAG=ON"],
     ),
+    "nghttp2/nghttp2": PackageDef(
+        rev="v1.54.0",
+        build_type="cmake",
+        config_env=["CXXFLAGS=-std=c++20"],
+        config_flags=[
+            "-DENABLE_LIB_ONLY=ON",
+            "-DENABLE_STATIC_LIB=ON",
+        ],
+    ),
     "nlohmann/json": PackageDef(
         rev="v3.11.2",
         build_type="cmake",