meson: Install headers

This was missed when creating the initial meson build.

Change-Id: I7bf85413d779d99e21e8cc2b5294ee4700d1d4fa
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meson.build b/meson.build
index 2ec535b..bc4f1a1 100644
--- a/meson.build
+++ b/meson.build
@@ -12,6 +12,10 @@
 ipmi_blob_dep = declare_dependency(
   include_directories: include_directories('.'))
 
+install_headers(
+  'blobs-ipmid/blobs.hpp',
+  subdir: 'blobs-ipmid')
+
 import('pkgconfig').generate(
   name: 'phosphor-ipmi-blobs',
   description: 'Phosphor Blob Transfer Interface',