Reduce golang requirement to go1.18

go1.21, the previous requirement, was released a few months ago, so not
all systems have adopted it.  go1.18 is old enough that most systems
should support it, but it introduces generics, which my testing code is
highly dependent on, so I can't easily go any earlier.

1 files changed, 1 insertions, 1 deletions

diff --git a/go.mod b/go.mod
index 3e9c6d8..d3ad6f5 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module aphopkins/radix_info
 
-go 1.21
+go 1.18