Drop support for EOL distros and Ubuntu Bionic

[christophebedard]

• Drop support for Melodic and Foxy, since they are now EOL
• Drop support for Ubuntu Bionic, since there is no longer an active ROS distro for it (used to be Melodic)
• Since there is no longer (and never will be) a common Ubuntu version for a ROS 1 distro and a ROS 2 distro, remove the test_multiple_ros_installations CI test job
• Update Windows binaries for Humble
• Update distros in README

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (6c3a899) 93.18% compared to head (69c3b23) 93.18%.

:exclamation: Current head 69c3b23 differs from pull request most recent head 263c477. Consider uploading reports for the commit 263c477 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #592 +/- ## ======================================= Coverage 93.18% 93.18% ======================================= Files 8 8 Lines 176 176 Branches 17 17 ======================================= Hits 164 164 Misses 12 12 ``` | [Impacted Files](https://app.codecov.io/gh/ros-tooling/setup-ros/pull/592?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-tooling) | Coverage Δ | | |---|---|---| | [src/package\_manager/apt.ts](https://app.codecov.io/gh/ros-tooling/setup-ros/pull/592?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-tooling#diff-c3JjL3BhY2thZ2VfbWFuYWdlci9hcHQudHM=) | `93.75% <ø> (ø)` | | | [src/setup-ros-windows.ts](https://app.codecov.io/gh/ros-tooling/setup-ros/pull/592?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-tooling#diff-c3JjL3NldHVwLXJvcy13aW5kb3dzLnRz) | `78.12% <ø> (ø)` | | | [src/setup-ros-linux.ts](https://app.codecov.io/gh/ros-tooling/setup-ros/pull/592?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-tooling#diff-c3JjL3NldHVwLXJvcy1saW51eC50cw==) | `97.72% <100.00%> (ø)` | | | [src/utils.ts](https://app.codecov.io/gh/ros-tooling/setup-ros/pull/592?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ros-tooling#diff-c3JjL3V0aWxzLnRz) | `90.32% <100.00%> (ø)` | |

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[christophebedard]

Yep, users can just keep using an older version of setup-ros/action-ros-ci, but they of course won't get new features.