Make sure to fetch tags.

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>
diff --git a/open_pdks/build-info.py b/open_pdks/build-info.py
index 128b2a6..1e085d4 100755
--- a/open_pdks/build-info.py
+++ b/open_pdks/build-info.py
@@ -18,6 +18,7 @@
 import subprocess
 import json
 
+GIT_FETCH_TAGS="git fetch --tags"
 GIT_DESCRIBE_CMD="git describe --long --always"
 GIT_LOG_CMD="git log -n 1 --stat"
 
@@ -46,6 +47,12 @@
 
 out_version = [0, 0, 0, 0]
 for k in versions:
+    # Make sure that we have tags.
+    subprocess.check_call(
+        GIT_FETCH_TAGS.split(),
+        cwd=versions[k]['dir'],
+    )
+
     v_str = subprocess.check_output(
         GIT_DESCRIBE_CMD.split(),
         cwd=versions[k]['dir'],