Replace http fetch of spdlog dep with git clone

Github doesn't promise byte for byte archives of specific commits, so
it's likely better to fetch this dep via git where we can specify the
specific commit we want to use.

Author: GrayHatter

WORKSPACE

@@ -1,4 +1,5 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
 
 # Bazel
 # =========================================================
@@ -140,12 +141,11 @@ http_archive(
 )
 
 # 1.11.0 + fixes for -Wshadow.
-http_archive(
+git_repository(
     name = "spdlog",  # MIT
     build_file = "//third_party:spdlog.BUILD",
-    sha256 = "6be1b1c8ec9ed82b1f5c4d793678d5d9446e000eb38bb53c7d470365171722fd",
-    strip_prefix = "spdlog-6df64c6c34997e298a81150b9ce55c440c6f503f",
-    url = "https://github.com/gabime/spdlog/archive/6df64c6c34997e298a81150b9ce55c440c6f503f.tar.gz",
+    commit = "6df64c6c34997e298a81150b9ce55c440c6f503f",
+    remote = "https://github.com/gabime/spdlog/",
 )
 
 http_archive(