reports: add GitHub Security Advisories

Using vulnreport fix, populate the GHSA IDs for all existing reports.

Change-Id: I09cabc16895994ccff1e2cab628a6c7b9d6a4bf4
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/388677
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: kokoro <noreply+kokoro@google.com>
diff --git a/reports/GO-2020-0012.yaml b/reports/GO-2020-0012.yaml
index 47b69eb..9bd2b4e 100644
--- a/reports/GO-2020-0012.yaml
+++ b/reports/GO-2020-0012.yaml
@@ -10,6 +10,8 @@
 published: 2021-04-14T20:04:52Z
 cves:
   - CVE-2020-9283
+ghsas:
+  - GHSA-ffhg-7mh4-33c4
 credit: Alex Gaynor, Fish in a Barrel
 symbols:
   - parseED25519