Set the isPermaLink attribute to false in the guid sub-element (g…

…o-gitea#28860)

Our `guid` is not a valid URL so according to the RSS spec the
`isPermaLink` attribute needs to be set to `false`.

Example:
```diff
<item>
  <title>yardenshoham opened issue &lt;a href=&#34;https://3000-yardenshoham-gitea-jqlxjixsez9.ws-us107.gitpod.io/yardenshoham/test/issues/2&#34;&gt;yardenshoham/test#2&lt;/a&gt;</title>
  <link>https://3000-yardenshoham-gitea-jqlxjixsez9.ws-us107.gitpod.io/yardenshoham/test/issues/2</link>
  <description>2#hey</description>
  <content:encoded><![CDATA[2#hey]]></content:encoded>
  <author>yardenshoham</author>
- <guid>355: https://3000-yardenshoham-gitea-jqlxjixsez9.ws-us107.gitpod.io/yardenshoham/test/issues/2</guid>
+ <guid isPermaLink="false">355: https://3000-yardenshoham-gitea-jqlxjixsez9.ws-us107.gitpod.io/yardenshoham/test/issues/2</guid>
  <pubDate>Tue, 16 Jan 2024 18:54:36 +0000</pubDate>
</item>
```

References:
-
https://www.rssboard.org/rss-specification#ltguidgtSubelementOfLtitemgt
- Fixes go-gitea#28734
- gorilla/feeds#78
- go-gitea#21550
- gorilla/feeds#107

Signed-off-by: Yarden Shoham <git@yardenshoham.com>

go.mod

@@ -306,6 +306,8 @@ replace github.com/shurcooL/vfsgen => github.com/lunny/vfsgen v0.0.0-20220105142
 
 replace github.com/nektos/act => gitea.com/gitea/act v0.2.51
 
+replace github.com/gorilla/feeds => github.com/yardenshoham/feeds v0.0.0-20240110072658-f3d0c21c0bd5
+
 exclude github.com/gofrs/uuid v3.2.0+incompatible
 
 exclude github.com/gofrs/uuid v4.0.0+incompatible

go.sum

@@ -578,8 +578,6 @@ github.com/gorilla/context v1.1.1 h1:AWwleXJkX/nhcU9bZSnZoi3h/qGYqQAGhq6zZe/aQW8
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=
 github.com/gorilla/css v1.0.0/go.mod h1:Dn721qIggHpt4+EFCcTLTU/vk5ySda2ReITrtgBl60c=
-github.com/gorilla/feeds v1.1.1 h1:HwKXxqzcRNg9to+BbvJog4+f3s/xzvtZXICcQGutYfY=
-github.com/gorilla/feeds v1.1.1/go.mod h1:Nk0jZrvPFZX1OBe5NPiddPw7CfwF6Q9eqzaBbaightA=
 github.com/gorilla/handlers v1.5.1 h1:9lRY6j8DEeeBT10CvO9hGW0gmky0BprnvDI5vfhUHH4=
 github.com/gorilla/handlers v1.5.1/go.mod h1:t8XrUpc4KVXb7HGyJ4/cEnwQiaxrX/hz1Zv/4g96P1Q=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
@@ -1060,6 +1058,8 @@ github.com/xi2/xz v0.0.0-20171230120015-48954b6210f8/go.mod h1:HUYIGzjTL3rfEspMx
 github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
 github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 h1:bAn7/zixMGCfxrRTfdpNzjtPYqr8smhKouy9mxVdGPU=
 github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673/go.mod h1:N3UwUGtsrSj3ccvlPHLoLsHnpR27oXr4ZE984MbSER8=
+github.com/yardenshoham/feeds v0.0.0-20240110072658-f3d0c21c0bd5 h1:3seWKGVhGoc66Ht5QlhQsr4xT2caDnFegsnh2NqvENU=
+github.com/yardenshoham/feeds v0.0.0-20240110072658-f3d0c21c0bd5/go.mod h1:WMib8uJP3BbY+X8Szd1rA5Pzhdfh+HCCAYT2z7Fza6Y=
 github.com/yohcop/openid-go v1.0.1 h1:DPRd3iPO5F6O5zX2e62XpVAbPT6wV51cuucH0z9g3js=
 github.com/yohcop/openid-go v1.0.1/go.mod h1:b/AvD03P0KHj4yuihb+VtLD6bYYgsy0zqBzPCRjkCNs=
 github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d/go.mod h1:rHwXgn7JulP+udvsHwJoVG1YGAP6VLg4y9I5dyZdqmA=

routers/web/feed/convert.go

@@ -244,6 +244,7 @@ func feedActionsToFeedItems(ctx *context.Context, actions activities_model.Actio
 			Title:       title,
 			Link:        link,
 			Description: desc,
+			IsPermaLink: "false",
 			Author: &feeds.Author{
 				Name:  act.ActUser.DisplayName(),
 				Email: act.ActUser.GetEmail(),