[ci] Only download build-bin artifacts

As part of a CI step, Azure Pipelines produces artifacts. These
artifacts are uploaded, and can be downloaded again in a subsequent
step. Currently, we download *all* artifacts, but we're only interested
in artifacts put into the $BIN_DIR directory (e.g.
`$REPO_TOP/build-bin`). Limit the download routine to only get those
artifacts to save download bandwidth (and time).

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/ci/download-artifacts-template.yml b/ci/download-artifacts-template.yml
index ff294ea..30f0256 100644
--- a/ci/download-artifacts-template.yml
+++ b/ci/download-artifacts-template.yml
@@ -16,6 +16,8 @@
     inputs:
       buildType: current
       targetPath: '$(BUILD_ROOT)/downloads'
+      # The first "path" segment is the name of the artifact.
+      pattern: "*-build-bin/**"
     displayName: 'Download upstream outputs'
   - bash: |
       set -e