patch 8.2.0140: CI does not test building doc tags

Problem:    CI does not test building doc tags.
Solution:   Add the vimtags/gcc build. Cleanup showing version. (Ozaki Kiichi,
            closes #5513)

ci/if_ver-1.vim

@@ -0,0 +1,25 @@
+" Print all interface versions for Ubuntu. Part 1.
+
+if 1
+  execute 'source' expand('<sfile>:h') .. '/if_ver-cmd.vim'
+
+  echo "*** Interface versions ***\n"
+
+  echo 'Lua:'
+  PrintVer lua print(_VERSION)
+
+  echo 'MzScheme:'
+  PrintVer mzscheme (display (version))
+
+  echo 'Perl:'
+  PrintVer perl print $^V
+
+  echo 'Ruby:'
+  PrintVer ruby print RUBY_VERSION
+
+  echo 'Tcl:'
+  PrintVer tcl puts [info patchlevel]
+
+  echo 'Python 2:'
+  PrintVer python print sys.version
+endif

ci/if_ver-2.vim

@@ -0,0 +1,8 @@
+" Print py3 interface versions for Ubuntu. Part 2.
+
+if 1
+  execute 'source' expand('<sfile>:h') .. '/if_ver-cmd.vim'
+
+  echo 'Python 3:'
+  PrintVer python3 print(sys.version)
+endif

ci/if_ver-cmd.vim

@@ -0,0 +1,12 @@
+" Provide 'PrintVer' command to print the interface versions.
+
+func s:print_ver(lang, ...)
+  if has(a:lang)
+    exec a:lang join(a:000)
+  else
+    echo 'N/A'
+  endif
+  echo ''
+endfunc
+
+command -nargs=+ PrintVer call <SID>print_ver(<f-args>)