internal/scan: consistently use - in testdata file names

Change-Id: Id71965f0d222a1b5f7b54aca98e0778c569fabcd
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/495865
Auto-Submit: Ian Cottrell <iancottrell@google.com>
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Julie Qiu <julieqiu@google.com>
diff --git a/internal/scan/testdata/multi_stacks.json b/internal/scan/testdata/multi-stacks.json
similarity index 100%
rename from internal/scan/testdata/multi_stacks.json
rename to internal/scan/testdata/multi-stacks.json
diff --git a/internal/scan/testdata/multi_stacks.txt b/internal/scan/testdata/multi-stacks.txt
similarity index 100%
rename from internal/scan/testdata/multi_stacks.txt
rename to internal/scan/testdata/multi-stacks.txt
diff --git a/internal/scan/testdata/no_vulns.json b/internal/scan/testdata/no-vulns.json
similarity index 100%
rename from internal/scan/testdata/no_vulns.json
rename to internal/scan/testdata/no-vulns.json
diff --git a/internal/scan/testdata/no_vulns.txt b/internal/scan/testdata/no-vulns.txt
similarity index 100%
rename from internal/scan/testdata/no_vulns.txt
rename to internal/scan/testdata/no-vulns.txt