DEV: Add .tool-versions file for package managers (#12808)

DEV: Add .tool-versions file for package managers (#12808)

diff --git a/.tool-versions b/.tool-versions
new file mode 100644
index 0000000..75d6469
--- /dev/null
+++ b/.tool-versions
@@ -0,0 +1,2 @@
+nodejs 15.14.0
+ruby 2.7.2

GitHub sha: a872df87

This commit appears in #12808 which was approved by eviltrout. It was merged by Falco.