Check exact version match

src/setup-elixir.js

@@ -67,9 +67,13 @@ async function getElixirVersion(spec, otpVersion) {
 }
 
 function getVersionFromSpec(spec, versions) {
+  if (versions.includes(spec)) {
+    return spec;
+  } else {
     const range = semver.validRange(spec)
     return semver.maxSatisfying(versions, range)
   }
+}
 
 async function getOtpVersions() {
   const result = await get("https://raw.githubusercontent.com/erlang/otp/master/otp_versions.table")