Update http:// links to https:// if available.

Also update some links that have been migrated.

Context: #6839.
RELNOTES=n/a
PiperOrigin-RevId: 583431708

Author: chaoren

.github/ISSUE_TEMPLATE/feature_addition_request.yaml

@@ -9,8 +9,8 @@ body:
 
 
         Be aware, though: most feature requests are not accepted, even if they're suggested by
-        a full-time Guava team member. [Feedback](http://stackoverflow.com/a/4543114/869736) from
-        our users indicates that they really appreciate Guava's high power-to-weight ratio. It's
+        a full-time Guava team member. [Feedback](https://stackoverflow.com/a/4543114) from our
+        users indicates that they really appreciate Guava's high power-to-weight ratio. It's
         important to us to keep Guava as easy to use and understand as we can. That means boiling
         features down to compact but powerful abstractions, and controlling feature bloat carefully.
 

.github/ISSUE_TEMPLATE/feature_enhancement_request.yaml

@@ -9,8 +9,8 @@ body:
 
 
         Be aware, though: most feature requests are not accepted, even if they're suggested by
-        a full-time Guava team member. [Feedback](http://stackoverflow.com/a/4543114/869736) from
-        our users indicates that they really appreciate Guava's high power-to-weight ratio. It's
+        a full-time Guava team member. [Feedback](https://stackoverflow.com/a/4543114) from our
+        users indicates that they really appreciate Guava's high power-to-weight ratio. It's
         important to us to keep Guava as easy to use and understand as we can. That means boiling
         features down to compact but powerful abstractions, and controlling feature bloat carefully.
 

CONTRIBUTING.md

@@ -21,7 +21,7 @@ for it.
 If the feature has merit, it will go through a thorough process of API design
 and review. Any code should come after this.
 
-[APIs]: http://en.wikipedia.org/wiki/Application_programming_interface
+[APIs]: https://en.wikipedia.org/wiki/Application_programming_interface
 [issue]: https://github.com/google/guava/issues
 
 Pull requests
@@ -53,7 +53,7 @@ Guidelines for any code contributions:
      [well-formed commit message][] for the change.
 
 [Java style guide]: https://google.github.io/styleguide/javaguide.html
-[well-formed commit message]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
+[well-formed commit message]: https://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
 
 #### Merging pull requests ####
 

README.md

@@ -80,16 +80,16 @@ flavor.
 ## Learn about Guava
 
 -   Our users' guide, [Guava Explained]
--   [A nice collection](http://www.tfnico.com/presentations/google-guava) of
+-   [A nice collection](https://www.tfnico.com/presentations/google-guava) of
     other helpful links
 
 ## Links
 
 -   [GitHub project](https://github.com/google/guava)
 -   [Issue tracker: Report a defect or feature request](https://github.com/google/guava/issues/new)
 -   [StackOverflow: Ask "how-to" and "why-didn't-it-work" questions](https://stackoverflow.com/questions/ask?tags=guava+java)
--   [guava-announce: Announcements of releases and upcoming significant changes](http://groups.google.com/group/guava-announce)
--   [guava-discuss: For open-ended questions and discussion](http://groups.google.com/group/guava-discuss)
+-   [guava-announce: Announcements of releases and upcoming significant changes](https://groups.google.com/group/guava-announce)
+-   [guava-discuss: For open-ended questions and discussion](https://groups.google.com/group/guava-discuss)
 
 ## IMPORTANT WARNINGS
 

guava-testlib/README.md

@@ -28,10 +28,10 @@ dependencies {
 
 ## Links
 
-- [GitHub project](https://github.com/google/guava)
-- [Issue tracker: Report a defect or feature request](https://github.com/google/guava/issues/new)
-- [StackOverflow: Ask "how-to" and "why-didn't-it-work" questions](https://stackoverflow.com/questions/ask?tags=guava+java)
-- [guava-discuss: For open-ended questions and discussion](http://groups.google.com/group/guava-discuss)
+-   [GitHub project](https://github.com/google/guava)
+-   [Issue tracker: Report a defect or feature request](https://github.com/google/guava/issues/new)
+-   [StackOverflow: Ask "how-to" and "why-didn't-it-work" questions](https://stackoverflow.com/questions/ask?tags=guava+java)
+-   [guava-discuss: For open-ended questions and discussion](https://groups.google.com/group/guava-discuss)
 
 ## IMPORTANT WARNINGS