docs: note Azure Linux in README (#731)

Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>

README.md

@@ -11,6 +11,7 @@
 Supported data sources:
 - Alpine (https://secdb.alpinelinux.org)
 - Amazon (https://alas.aws.amazon.com/AL2/alas.rss & https://alas.aws.amazon.com/AL2022/alas.rss)
+- Azure (https://github.com/microsoft/AzureLinuxVulnerabilityData)
 - Debian (https://security-tracker.debian.org/tracker/data/json & https://salsa.debian.org/security-tracker-team/security-tracker/raw/master/data/DSA/list)
 - GitHub Security Advisories (https://api.github.com/graphql)
 - NVD (https://services.nvd.nist.gov/rest/json/cves/2.0)