being explicit about date formats for blog posts

docs/input/blog/posts/2021-07-11-hello-world.md

@@ -1,6 +1,6 @@
 Title: Hello, World
 Description: To help track new releases, updates and planning for Spectre.Console, we've added a new blog to the documentation.
-Published: 20210711
+Published: 2021-07-11
 Category: News
 ---
 

docs/input/blog/posts/2021-07-19-spectre-console-0.41-released.md

@@ -1,6 +1,6 @@
 Title: Spectre.Console 0.41 released!
 Description: In this release we (mostly Phil) have been focusing on getting the new fancy Roslyn Analyzers out the door...
-Published: 20210719
+Published: 2021-07-19
 Category: Release Notes
 Excluded: false
 ---

docs/input/blog/posts/2021-12-16-spectre-console-0.43-released.md

@@ -1,6 +1,6 @@
 Title: Spectre.Console 0.43 released!
 Description: Now with .NET 6 support... and more!
-Published: 20211216
+Published: 2021-12-16
 Category: Release Notes
 Excluded: false
 ---

docs/input/blog/posts/2022-03-27-spectre-console-0.44-released.md

@@ -1,6 +1,6 @@
 Title: Spectre.Console 0.44 released!
 Description: Alternate screen buffers, better exception rendering... and more!
-Published: 20220327
+Published: 2022-03-27
 Category: Release Notes
 Excluded: false
 ---

docs/input/blog/posts/2022-09-10-spectre-console-0.45-released.md

@@ -1,6 +1,6 @@
 Title: Spectre.Console 0.45 released!
 Description: .NET 5 dropped, Spectre.Console.Cli moved to separate NuGet package
-Published: 20220910
+Published: 2022-09-10
 Category: Release Notes
 Excluded: false
 ---

docs/input/blog/posts/BLOG_TEMPLATE.md

@@ -1,6 +1,6 @@
 Title: Short title, less than 50 characters
 Description: Longer description, with optional *bold* and **italic** characters. Shouldn't be TOO long but can span multiple lines.
-Published: 20210710
+Published: 2021-07-10
 Category: Release Notes | News | or whatever
 Excluded: true
 ---