Update the default version of smart dim component

Version "20200601.0" is basically the same as "2019.11.12.0", only with
a generic metrics model name in the meta JSON file.

Note: The version schema is changed from "yyyy.mm.dd.sub" to
"yyyymmdd.sub", that's because Omaha server automatically changes
"2020.06.01.0" to "2020.6.1.0", while we want to keep the origin date
string. All the future versions will be "yyyymmdd.sub".

Bug: 1067048
Test: Tested on DUT
Change-Id: I6b738698fd9b06c9edc666803630115509a736fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2226104
Commit-Queue: Xinglong Luan <alanlxl@chromium.org>
Reviewed-by: Andrew Moylan <amoylan@chromium.org>
Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774399}

chrome/browser/component_updater/smart_dim_component_installer.cc

@@ -40,7 +40,7 @@ const base::FilePath::CharType kSmartDimModelFileName[] =
 const base::FilePath::CharType kSmartDimMetaJsonFileName[] =
     FILE_PATH_LITERAL("smart_dim_meta.json");
 
-const char kDefaultVersion[] = "2019.11.12.0";
+const char kDefaultVersion[] = "20200601.0";
 
 constexpr base::FeatureParam<std::string> kVersion{
     &chromeos::features::kSmartDimExperimentalComponent,