CI: use OTP 27 for tests

Erlang 27 is fully supported in main and v4.1.x. Support for Erlang 26
in v4.1 remains. It's better to "drop" erlang 26 from CI because, at the
moment, our PRs and commits to main trigger about 270 jobs. If we just
add '27' to the matrix, we would spawn ~216 more jobs, totalling around
496 jobs per PR and commit to main. That's simply too much, because it's
reaching the usage limits of Github Actions [1], namely the 256 limit of
matrix jobs.

[1]
https://docs.github.com/en/actions/administering-github-actions/usage-limits-billing-and-administration#usage-limits

Author: Zerpet

.github/workflows/test-authnz.yaml

@@ -30,11 +30,11 @@ jobs:
       fail-fast: false
       matrix:
         erlang_version:
-        - "26.2"
+        - "27.3"
         browser:
         - chrome
         include:
-        - erlang_version: "26.2"
+        - erlang_version: "27.3"
           elixir_version: 1.17.3
     env:
       SELENIUM_DIR: selenium

.github/workflows/test-make.yaml

@@ -62,8 +62,7 @@ jobs:
       fail-fast: false
       matrix:
         erlang_version:
-        - '26'
-##        - '27'
+        - '27'
         elixir_version:
         - '1.17'
         metadata_store:
@@ -82,8 +81,7 @@ jobs:
       fail-fast: false
       matrix:
         erlang_version:
-        - '26'
-##        - '27'
+        - '27'
         elixir_version:
         - '1.17'
         metadata_store:

.github/workflows/test-management-ui-for-pr.yaml

@@ -15,11 +15,11 @@ jobs:
       fail-fast: false
       matrix:
         erlang_version:
-        - "26.2"
+        - "27.3"
         browser:
         - chrome
         include:
-        - erlang_version: "26.2"
+        - erlang_version: "27.3"
           elixir_version: 1.17
     env:
       SELENIUM_DIR: selenium

.github/workflows/test-management-ui.yaml

@@ -22,11 +22,11 @@ jobs:
       fail-fast: false
       matrix:
         erlang_version:
-        - "26.2"
+        - "27.3"
         browser:
         - chrome
         include:
-        - erlang_version: "26.2"
+        - erlang_version: "27.3"
           elixir_version: 1.17.3
     env:
       SELENIUM_DIR: selenium