Return latest version if requested version is any

I believe this is a bug in semver crate but according to NPM people, and
@steveklabnik; a version like "0.1.0-pre.0" or "0.1.0-beta.0" *is not a
real version* and any version that contains a pre-release string is getting
different treatment by semver.

IMO this is utterly wrong. Docs.rs is probably the first victim of this
behavior and it will affect more in future. `*` means any and it should
match any version. It doesn't matter if a version have a pre-release string
or not. Even older versions of node's semver were matching "*" for any
version. I don't know why they changed this behavior but I am not surprised
any means "anything except a version that contains pre-release" in JS
world.

Fixes: rust-lang#80
Ref: dtolnay/semver#98

Author: onur

src/web/mod.rs

@@ -231,6 +231,12 @@ fn match_version(conn: &Connection, name: &str, version: Option<&str>) -> Option
         versions_sem
     };
 
+    // semver is acting weird for '*' (any) range if a crate only have pre-release versions
+    // return first version if requested version is '*'
+    if req_version == "*" && !versions_sem.is_empty() {
+        return Some(format!("{}", versions_sem[0]));
+    }
+
     for version in &versions_sem {
         if req_sem_ver.matches(&version) {
             return Some(format!("{}", version))