[CI] run `opam list` which will print ocaml version as well as those of ocaml libraries

.travis.yml

@@ -85,6 +85,7 @@ install_linux: &install_linux
   - opam update
   - opam pin add haxe . --no-action
   - opam install haxe --deps-only
+  - opam list
   # Build haxe
   - make package_src -s
   - opam config exec -- make -s STATICLINK=1 libs
@@ -135,6 +136,7 @@ install_osx: &install_osx
   - opam update
   - opam pin add haxe . --no-action
   - opam install haxe --deps-only
+  - opam list
   # Build haxe
   - make -s STATICLINK=1 "LIB_PARAMS=/usr/local/opt/zlib/lib/libz.a /usr/local/lib/libpcre.a" libs
   - make -s -j STATICLINK=1 "LIB_PARAMS=/usr/local/opt/zlib/lib/libz.a /usr/local/lib/libpcre.a" haxe

appveyor.yml

@@ -46,6 +46,7 @@ install:
     - '%CYG_ROOT%/bin/bash -lc "opam update --yes"'
     - '%CYG_ROOT%/bin/bash -lc "opam pin add haxe \"$APPVEYOR_BUILD_FOLDER\" --no-action --yes"'
     - '%CYG_ROOT%/bin/bash -lc "opam install haxe --deps-only --yes"'
+    - '%CYG_ROOT%/bin/bash -lc "opam list"'
     # Install php
     - choco install php --version 7.2.0 -y
     - echo extension=php_openssl.dll >> C:\tools\php72\php.ini