Fix two regex issues in the github actions

Directory name check wasn't allowing _2 https://google.github.io/security-research/kernelctf/rules.html#exploit-pr-file-structure

Regex in schema wasn't allowing mitigation-v3b

kernelctf/check-submission.py

@@ -27,7 +27,7 @@
 prFiles = checkList(prFiles, lambda f: f.startswith(POC_FOLDER), f"The following files are outside of the `{POC_FOLDER}` folder which is not allowed")
 
 subDirName = checkOnlyOne(subdirEntries(prFiles, POC_FOLDER), "Only one submission is allowed per PR. Found multiple submissions")
-checkRegex(subDirName, r"^CVE-\d+-\d+(_lts|_cos|_mitigation)+$", f"The submission folder name is invalid (`{subDirName}`)")
+checkRegex(subDirName, r"^CVE-\d+-\d+(_lts|_cos|_mitigation)+(_\d+)?$", f"The submission folder name is invalid (`{subDirName}`)")
 
 print(f"[-] Processing submission... Folder = {subDirName}")
 cve, *targets = subDirName.split('_')

kernelctf/metadata.schema.v3.json

@@ -80,7 +80,7 @@
             "type": "object",
             "additionalProperties": false,
             "patternProperties": {
-                "^((lts-[0-9]+.[0-9]+(\\.[0-9]+)?)|(mitigation-(v[0-9]+-)?[0-9]+\\.[0-9]+(\\.[0-9]+)?)|(cos-[0-9]{2,}-[0-9]+\\.[0-9]+\\.[0-9]+)|extra-.*)$": {
+                "^((lts-[0-9]+.[0-9]+(\\.[0-9]+)?)|(mitigation-(v[0-9]+[a-z]?-)?[0-9]+\\.[0-9]+(\\.[0-9]+)?)|(cos-[0-9]{2,}-[0-9]+\\.[0-9]+\\.[0-9]+)|extra-.*)$": {
                     "type": "object",
                     "required": ["uses", "requires_separate_kaslr_leak", "stability_notes"],
                     "properties": {