openbmc-build-scripts: add `libcurl` dependency to test redflish client

On some system designs we need a "redfish client" to query metrics from
an http(s) server running on an Satellite Management Controller
instance, such as the Nvidia HMC[1], and forward those metrics to BMC
monitoring the devices.

There is a design document proposal available[2].  Adding `libcurl`
enables prototyping of the "Redfish client" instances following this
design document and run them on the official container.

[1]: https://github.com/openbmc/entity-manager/blob/master/configurations/nvidia_hmc.json#L14
[2]: https://gerrit.openbmc.org/c/openbmc/docs/+/75641/9/designs/redfish-client.md#154

Change-Id: I4848fb76edffb09d12891460972f9fb676d0d48a
Signed-off-by: Anirban Banerjee <anirbanb@meta.com>
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index afcdc8c..f925432 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -846,6 +846,7 @@
     libcjson-dev \
     libconfig++-dev \
     libcryptsetup-dev \
+    libcurl4-openssl-dev \
     libdbus-1-dev \
     libevdev-dev \
     libgpiod-dev \