Fix since_last_release.nu script (nushell#385)

Missed update of fetch to `http get`

Author: sholderbach

make_release/since_last_release.nu

@@ -1,5 +1,5 @@
-# fetch https://api.github.com/repos/nushell/nushell/pulls?q=is%3Apr+merged%3A%3E%3D2021-04-20+ | select html_url user.login title body
-# fetch https://api.github.com/search/issues?q=repo:nushell/nushell+is:pr+is:merged+merged:%3E2021-05-08 | get items | select html_url user.login title body
+# http get https://api.github.com/repos/nushell/nushell/pulls?q=is%3Apr+merged%3A%3E%3D2021-04-20+ | select html_url user.login title body
+# http get https://api.github.com/search/issues?q=repo:nushell/nushell+is:pr+is:merged+merged:%3E2021-05-08 | get items | select html_url user.login title body
 # Repos to monitor
 
 def do-work [] {
@@ -28,7 +28,7 @@ def do-work [] {
     let entries = ($site_table | each { |row|
         let query_string = $"($query_prefix)($row.repo)($query_suffix)"
         # this is for debugging the rate limit. comment it out if things are working well
-        # fetch -u $env.GITHUB_USERNAME -p $env.GITHUB_PASSWORD https://api.github.com/rate_limit | get resources | select core.limit core.remaining graphql.limit graphql.remaining integration_manifest.limit integration_manifest.remaining search.limit search.remaining
+        # http get -u $env.GITHUB_USERNAME -p $env.GITHUB_PASSWORD https://api.github.com/rate_limit | get resources | select core.limit core.remaining graphql.limit graphql.remaining integration_manifest.limit integration_manifest.remaining search.limit search.remaining
         let site_json = (http get -u $env.GITHUB_USERNAME -p $env.GITHUB_PASSWORD $query_string | get items | select html_url user.login title)
 
         $"## ($row.site)(char nl)(char nl)"