Update module github.com/mailgun/mailgun-go/v4 to v4.20.4 (#46)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

go.mod

@@ -3,7 +3,7 @@ module github.com/theopenlane/newman
 go 1.23.3
 
 require (
-	github.com/mailgun/mailgun-go/v4 v4.20.2
+	github.com/mailgun/mailgun-go/v4 v4.20.4
 	github.com/microcosm-cc/bluemonday v1.0.27
 	github.com/resend/resend-go/v2 v2.13.0
 	github.com/sendgrid/rest v2.6.9+incompatible

go.sum

@@ -69,8 +69,8 @@ github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnr
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
 github.com/mailgun/errors v0.4.0 h1:6LFBvod6VIW83CMIOT9sYNp28TCX0NejFPP4dSX++i8=
 github.com/mailgun/errors v0.4.0/go.mod h1:xGBaaKdEdQT0/FhwvoXv4oBaqqmVZz9P1XEnvD/onc0=
-github.com/mailgun/mailgun-go/v4 v4.20.2 h1:ZNrJ6mAAXSA1K6gnlDBNkoAa4nseP5c1U3WOxXOHqKc=
-github.com/mailgun/mailgun-go/v4 v4.20.2/go.mod h1:768NjUvsxW8Ga8fHIPITmr5f/U8qmnQqnZ3/cs3StUc=
+github.com/mailgun/mailgun-go/v4 v4.20.4 h1:9R10uxZ2ELCzMdalUbQ7g4q3sHY0s7qtnIvODgsdAGQ=
+github.com/mailgun/mailgun-go/v4 v4.20.4/go.mod h1:768NjUvsxW8Ga8fHIPITmr5f/U8qmnQqnZ3/cs3StUc=
 github.com/microcosm-cc/bluemonday v1.0.27 h1:MpEUotklkwCSLeH+Qdx1VJgNqLlpY2KXwXFM08ygZfk=
 github.com/microcosm-cc/bluemonday v1.0.27/go.mod h1:jFi9vgW+H7c3V0lb6nR74Ib/DIB5OBs92Dimizgw2cA=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=