write a simple directory name linter

You can explore the behavior of this script by setting up some temporary
directories:
```bash
mkdir -p /tmp/linting/2.0.0
mkdir -p /tmp/linting/yeah_whatever_linter
```

Then, run the linter
```bash
cd /tmp/linting
nu ./lint_directories.nu
```

lint_directories.nu

@@ -0,0 +1,15 @@
+# List any directory that does not follow a SemVer naming pattern
+# For example
+# - 1.0.1 is a valid directory name.
+# - yeah_whatever_linter is not a valid directory name.
+def ls-incorrect-dirs [] {
+    ls | where type == 'Dir' && name != 'scripts'| match -v name '(\d+\.){2,}\d$'
+}
+let incorrect_count = $(ls-incorrect-dirs | length);
+if $incorrect_count > 0 {
+  echo 'The following directories are named incorrectly:'
+	ls-incorrect-dirs
+	exit 1
+} {
+	exit 0
+}