libgit2: Bump to v1.8.0-alpha

Author: bnjmnt4n

libgit2-sys/build.rs

@@ -7,7 +7,7 @@ use std::process::Command;
 /// Tries to use system libgit2 and emits necessary build script instructions.
 fn try_system_libgit2() -> Result<pkg_config::Library, pkg_config::Error> {
     let mut cfg = pkg_config::Config::new();
-    match cfg.range_version("1.7.2".."1.8.0").probe("libgit2") {
+    match cfg.range_version("1.8.0-alpha".."1.9.0").probe("libgit2") {
         Ok(lib) => {
             for include in &lib.include_paths {
                 println!("cargo:root={}", include.display());